WO2010067814A1 - Substrate and method for manufacturing substrate - Google Patents

Substrate and method for manufacturing substrate Download PDF

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Publication number
WO2010067814A1
WO2010067814A1 PCT/JP2009/070587 JP2009070587W WO2010067814A1 WO 2010067814 A1 WO2010067814 A1 WO 2010067814A1 JP 2009070587 W JP2009070587 W JP 2009070587W WO 2010067814 A1 WO2010067814 A1 WO 2010067814A1
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WIPO (PCT)
Prior art keywords
substrate
reflection surface
region
main surface
light
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PCT/JP2009/070587
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French (fr)
Japanese (ja)
Inventor
健良 増田
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住友電気工業株式会社
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Filing date
Publication date
Application filed by 住友電気工業株式会社 filed Critical 住友電気工業株式会社
Priority to EP09831918A priority Critical patent/EP2378542A1/en
Priority to CN200980149548XA priority patent/CN102246265A/en
Priority to US13/133,284 priority patent/US20110241022A1/en
Priority to CA2746568A priority patent/CA2746568A1/en
Publication of WO2010067814A1 publication Critical patent/WO2010067814A1/en

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01VGEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00Prospecting or detecting by optical means
    • G01V8/10Detecting, e.g. by using light barriers
    • G01V8/12Detecting, e.g. by using light barriers using one transmitter and one receiver
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002Preparing wafers
    • H01L21/02005Preparing bulk and homogeneous wafers
    • H01L21/02008Multistep processes
    • H01L21/0201Specific process step
    • H01L21/02021Edge treatment, chamfering
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306Chemical or electrical treatment, e.g. electrolytic etching
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor

Definitions

  • the present invention relates to a substrate and a method for manufacturing the substrate, and more specifically to a substrate that can be recognized by a sensor even if it is transparent, and a method for manufacturing the substrate.
  • a semiconductor element such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor)
  • MOSFET Metal Oxide Semiconductor Field Effect Transistor
  • a semiconductor element is formed in the central region.
  • the main surface refers to the surface having the largest area among the surfaces. Therefore, no semiconductor element is formed in a region within a certain distance from the outer periphery of the semiconductor substrate. This is because such a semiconductor element formed near the outer periphery of the main surface, that is, in the end region, may have reduced reliability such as electrical characteristics.
  • an ID mark is formed in a region near the outer periphery of the main surface of the semiconductor substrate, that is, an end portion where no semiconductor element is formed.
  • the ID mark is used for consistent production management when performing a process for manufacturing a semiconductor device in which a large number of semiconductor elements are formed on the main surface of the semiconductor substrate.
  • numbers, characters, barcodes, etc. for identifying each semiconductor substrate may be arranged as ID marks at the end of the main surface of the semiconductor substrate.
  • an ID mark for example, a mark in which a large number of dots (concave portions) are formed at the end of the main surface of a semiconductor substrate has been used.
  • the semiconductor substrate is identified in the end region of the main surface of the semiconductor substrate.
  • This is an arrangement of a set of dots for the purpose.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2004-200355
  • the formed dots are polished and flattened by a chemical mechanical polishing process (CMP process) which is a subsequent process.
  • CMP process chemical mechanical polishing process
  • a semiconductor wafer in which a recess that does not come into contact with a polishing cloth for performing a CMP process is formed and dots are formed on the bottom surface of the recess. .
  • the shape of the end portion of the main surface of the substrate has been processed so as to be an end surface having a certain inclination angle with respect to the main surface so as to suppress chipping.
  • Bevel cut has been mainly used. Specifically, a surface that forms a predetermined angle with both main surfaces so as to intersect each of one main surface of the substrate and the other main surface of the substrate facing the one main surface, The end surface of the substrate is formed at the end of the substrate.
  • FIG. 15 is a schematic view showing a state in which a round is applied to the end portion of the substrate.
  • a substrate 20 shown in FIG. 15 has a special end processing of a curved surface called a round at the end of the main surface. That is, a curved surface (on the left side in FIG. 15) connecting one main surface (the upper surface in FIG. 15) of the substrate 20 and the other main surface (the lower surface in FIG. 15) located on the opposite side of the one main surface.
  • An end portion which is a semicircular portion) is provided, and the curved surface is used as an end surface of the substrate.
  • a red or infrared LED light emitting diode
  • LD laser diode
  • Si silicon
  • Si which has been mainly used as a conventional semiconductor substrate, absorbs red light or infrared light, so that it is possible to easily detect a semiconductor substrate made of silicon using these lights. is there.
  • a substrate 20 for example, a semiconductor substrate such as Si
  • red light or infrared light with respect to the one main surface (upper surface in FIG. 15). Irradiate light.
  • a photoelectric sensor 30 for recognizing the light beam 10 such as incident red light is installed in a region facing the main surface opposite to the one main surface of the substrate 20 (the lower surface in FIG. 15). Keep it. Then, when the substrate 20 does not exist, the light beam 10 irradiated from above one main surface of the substrate 20 enters the photoelectric sensor 30 as shown in FIG. At this time, it can be recognized that the substrate 20 does not exist when the photoelectric sensor 30 detects the light beam 10.
  • the photoelectric sensor 30 can detect the presence of the substrate 20.
  • a semiconductor element semiconductor device using a compound semiconductor such as silicon carbide (SiC) instead of Si has been attracting attention as a material for realizing a high-frequency power device and a heat and radiation resistant device.
  • SiC silicon carbide
  • a compound semiconductor such as SiC or GaN has a wider band gap (forbidden band width) and a higher dielectric breakdown electric field strength than Si, and a semiconductor device using the compound semiconductor is, for example, a semiconductor using Si. This is because it has superior switching characteristics and a higher withstand voltage than devices.
  • substrates made of such compound semiconductors substrates made of SiC, GaN, or the like are transparent, so that light irradiated to the substrate is less likely to be reflected by the substrate, and most of the light passes through the substrate. . Therefore, if the substrate 20 in FIG. 15 is a transparent substrate as described above, even if the substrate 20 is irradiated with light rays 10 such as red light or infrared light as shown in FIG. Compared with the case where the light beam 10 is applied to the substrate made of the above, the ratio of the light beam 10 reflected by the substrate 20 is reduced (that is, the ratio of the light beam 10 transmitted through the substrate 20 is increased). For this reason, it becomes difficult for the photoelectric sensor 30 to recognize the presence of the substrate 20 due to the intensity change of the light beam 10.
  • the semiconductor using the conventional Si substrate is used. It is conceivable to use the manufacturing apparatus used for manufacturing the apparatus.
  • the conventional method for detecting the presence of the Si substrate as described above it is difficult to accurately detect the presence of the transparent substrate. For this reason, it is difficult to divert the manufacturing apparatus used for the production of the semiconductor device using the conventional Si substrate as it is to the manufacture of the semiconductor device using the transparent substrate.
  • a detection method different from the conventional one is used to detect the presence of the transparent substrate, a significant modification of the manufacturing apparatus is required, resulting in problems such as an increase in the cost of the manufacturing apparatus. Become.
  • the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a substrate that can be detected by the same technique as a conventional Si substrate even if it is transparent, and a method for manufacturing the substrate. Is to provide.
  • the substrate according to the present invention is a transparent substrate, and is a substrate provided with a detection region which is formed on at least a part of the end portion of the substrate and has a light transmittance smaller than the light transmittance at the central portion of the substrate. .
  • a transparent substrate refers to a substrate having a low absorption rate (high transmittance) of light having a predetermined wavelength (for example, visible light (red light) or infrared light), for example, having a predetermined wavelength.
  • a substrate transparent to visible light is a region facing one main surface of the substrate and a region facing the other main surface located on the opposite side of the one main surface of the substrate. Means a substrate that can be visually observed through the substrate.
  • a part of the main surface of the substrate (here, the end portion) is used as a detection region, and the other main surface located on the opposite side of the main surface from the region facing the one main surface of the substrate in the detection region.
  • the ratio (transmittance) at which light is transmitted to the region facing the substrate is made smaller than the similar transmittance in the region other than the detection region (here, the central portion) on the main surface of the substrate.
  • the conventional Si substrate detection apparatus can be used for the detection of the substrate. Therefore, the manufacturing apparatus used in the manufacturing process of the semiconductor device using the conventional Si substrate can be used for the manufacturing process of the semiconductor device using the transparent substrate described above.
  • the semiconductor element or the like is usually not formed at the end of the substrate, the number of elements obtained from the substrate is reduced even if the detection region as described above is formed at the end of the substrate (elements of the element). There is little possibility that production efficiency will decrease.
  • the detection region described above preferably includes a total reflection surface that totally reflects light incident on the detection region. If the light incident on the detection region is totally reflected, almost all the light incident on the detection region is reflected on the surface of the detection region where the light is incident. For this reason, the light incident on the detection region enters the inside of the substrate from the detection region, and hardly transmits to the outside of the substrate from the back surface (the main surface opposite to the side on which the light is incident). As described above, since light traveling in the direction intersecting the main surface of the substrate is blocked in the substrate, the sensor that senses transmission of light can recognize (detect) the presence of the substrate.
  • the detection region described above may include an irregular reflection surface that irregularly reflects light incident on the detection region. If the light incident on the detection region is diffusely reflected, most of the light incident on the detection region is reflected on the surface of the detection region where the light is incident. For this reason, as in the case of including the total reflection surface described above, most of the light incident on the detection region is reflected by the presence of the substrate, so that the photoelectric sensor recognizes (detects) the presence of the substrate. Can do.
  • the substrate according to the present invention preferably contains at least one selected from the group consisting of SiC, GaN (gallium nitride), sapphire, AlN (aluminum nitride), and diamond. Since these are transparent substrates, when a semiconductor device is formed using these substrates, the presence of the substrate is detected by a sensor by providing a detection region with reduced light transmittance as described above. It can be easily detected.
  • the step of preparing a transparent substrate and the light transmittance in at least a part of the end portion of the substrate are made smaller than the light transmittance in the central portion of the substrate.
  • a process of performing processing As described above, in a transparent substrate, light such as visible light (for example, red light) or infrared light that is incident on one main surface usually passes through the inside of the substrate. The light is emitted from the main surface (back surface) opposite to the main surface. For this reason, it is difficult to detect the presence of a transparent substrate using a sensor such as a photoelectric sensor.
  • a process of forming a region (detection region) in which the transmittance of incident light is reduced is provided on a part of the substrate.
  • reducing the transmittance of light incident on a part of a substrate means that the transmittance of light in the region of the substrate is other than the region of the substrate (that is, the transmittance is reduced).
  • the processing is performed so that the light transmittance is 10% or less (in the region not processed to be reduced).
  • the senor can recognize that the amount of light passing through the inside of the substrate and transmitting to the outside of the substrate is reduced through the detection region. Therefore, the sensor can detect the presence of a transparent substrate.
  • the step of performing the above-described processing includes a step of forming a total reflection surface that totally reflects light incident on at least a part of the end portion.
  • the sensor can detect the presence of the substrate from the change in light transmittance in the detection region. If the substrate manufacturing method including the step of forming the total reflection surface as described above is used, a transparent substrate that can easily detect the presence of the substrate (by detecting a change in light transmittance) is formed by a sensor. be able to.
  • the process of forming the total reflection surface described above includes a process of machining at least a part of the end.
  • the step of forming the total reflection surface described above may include a step of laser processing at least a part of the end portion. If these processing methods are used, an arbitrary region on the surface of the substrate can be easily processed into an arbitrary shape (so as to be the total reflection surface). Therefore, by using these processing methods, it is possible to easily form a total reflection surface, so that detection of reducing the ratio (transmittance) of light incident from one main surface of the substrate to the outside of the substrate is reduced. The region can be easily formed.
  • the step of performing the above-described processing may include a step of forming an irregular reflection surface that irregularly reflects light incident on at least a part of the end portion. Similarly to the total reflection surface, the irregular reflection surface reflects light incident on a part of the end portion (detection region) of the substrate by the irregular reflection surface of the substrate, so that the light passes through the substrate and is on the back side. Permeation to the For this reason, even when the irregular reflection surface is formed, the presence of the substrate can be easily detected by the sensor as in the case where the total reflection surface is formed.
  • the step of forming the irregular reflection surface described above also includes a step of machining at least a part of the end portion as in the step of forming the total reflection surface described above.
  • the step of forming the irregular reflection surface described above may include a step of laser processing at least a part of the end portion. If these processing methods are used, an arbitrary region on the surface of the substrate can be easily processed into an arbitrary shape that becomes a diffusely reflecting surface. Therefore, the irregular reflection surface can be easily formed by using these processing methods. For this reason, it is possible to easily form a detection region that reduces the transmittance of light incident from the main surface of the substrate.
  • the step of forming the irregular reflection surface includes a step of introducing an impurity into at least a part of the end portion, and a step of increasing the surface roughness of the surface of the region into which the impurity is introduced. And may be included.
  • the step of increasing the surface roughness of the surface may include a step of etching the surface layer in the region where the impurity is introduced, or a step of heat treating the surface layer in the region where the impurity is introduced. By performing etching or heat treatment, an uneven portion can be formed on the surface of the region where the impurity is introduced, and the surface roughness can be increased.
  • the region can be a diffuse reflection surface. For this reason, the irregular reflection surface which should become a detection area
  • the step of forming the irregular reflection surface includes a step of forming a thin film on at least a part of the end portion. That is, by increasing the surface roughness of a predetermined region of the main surface of the substrate as described above, a thin film that can be used as the irregular reflection surface is formed on the main surface of the substrate instead of making the region an irregular reflection surface. Also good. An irregular reflection surface made of a thin film formed in this way can also exhibit the same effects as the irregular reflection surface formed by increasing the surface roughness.
  • the step of forming the total reflection surface may include a step of forming a thin film on at least a part of the end portion. As the thin film, any thin film whose surface is a total reflection surface can be used. In this case as well, the same effect as when the total reflection surface is formed by machining or the like can be obtained.
  • the present invention it is possible to provide a substrate that can be recognized by a sensor even if it is transparent, and a method for manufacturing the substrate.
  • a substrate 1 according to Embodiment 1 of the present invention has a predetermined thickness (vertical direction in FIG. 1), and is a transparent material used for a semiconductor device such as a high frequency power device or a heat / radiation resistant device. It is a substrate.
  • the substrate 1 is depicted in a trapezoidal shape, but in actuality, a flat plate having a thickness (vertical direction in FIG. 1) of, for example, about 1 mm and a diameter (horizontal direction of FIG. It has a shape.
  • a double wavy line is used to indicate that the width in the left-right direction is omitted.
  • the substrate 1 in FIG. 1 is a transparent substrate as described above.
  • the substrate 1 is made of a material containing at least one selected from the group consisting of SiC, GaN, sapphire, AlN, diamond, for example. Is preferred.
  • the substrate 1 made of these materials can be used as a substrate for a semiconductor element (semiconductor device) such as a power device using a compound semiconductor.
  • a light beam 10 (light) transmitted from the upper main surface side of the substrate 1 to the lower main surface (back surface) side in a direction intersecting (substantially perpendicular) the main surface. 1 passes through the inside of the substrate 1 at a high rate in the central portion (the central portion in the left-right direction in FIG. 1), and exits from the lower main surface to the outside of the substrate 1.
  • the light beam 10 may be visible light such as red light, or may be non-visible light such as infrared light.
  • the substrate 1 is preferably transparent to light having a wavelength of 200 nm to 800 nm.
  • the substrate 1 is particularly preferably transparent to light having a wavelength of 300 nm to 700 nm. If light having the above-described wavelength is used as the light beam 10, it can be operated as a highly accurate sensor.
  • the light beam 10 incident on the edge of the substrate 1 has the same wavelength and the same intensity as the light beam 10 incident on the central portion of the substrate 1.
  • the light beam 10 incident on the central portion of 1 is not transmitted through the substrate 1, but is totally reflected by the total reflection surface 2 of the detection region existing at least at a part of the end portion of the substrate 1.
  • the detection region is a region having a transmittance of the light beam 10 that is smaller than the transmittance of the light beam 10 in the central portion of the substrate 1.
  • the entire region in the left-right direction (outer peripheral edge of the substrate 2) in FIG. 1 where the total reflection surface 2 is formed is referred to as a detection region.
  • the detection region not only the total reflection surface 2 but also the outer peripheral end portion on the back surface side of the substrate 1 facing the photoelectric sensor 30 in FIG.
  • the detection region is formed by providing a total reflection surface 2 having a predetermined angle with respect to the main surface of the substrate 1. That is, the total reflection surface 2 totally reflects the light beam 10 in the detection region, and thus the ratio (transmittance) of the light beam 10 irradiated to the detection region through the substrate 1 is set to the light beam 10 in the region other than the detection region. Exerts the function of making the ratio smaller than the ratio of transmitting through the substrate 1. Therefore, for example, as shown in FIG. 1, when the light beam 10 is incident on the substrate 1 from a direction intersecting (perpendicular) to the main surface of the substrate 1, the light beam 10 incident on the total reflection surface 2 is totally reflected.
  • the total reflection surface 2 is an inclined surface having a predetermined angle ⁇ with respect to the main surface of the substrate 1 (left and right direction in FIG. 1) so that the angle can cause total reflection at the surface 2. Further, it is preferable that the surface of the total reflection surface 2 has such a small surface roughness that the light beam 10 incident on the total reflection surface 2 can be totally reflected without causing irregular reflection. In this way, the light beam 10 incident on the total reflection surface 2 is totally reflected as shown in FIG.
  • the photoelectric sensor 30 can recognize that the light beam 10 is blocked by the presence of the substrate 1 disposed on the photoelectric sensor 30. As a result, the presence of the substrate 1 can be detected by a change in the amount of light detected by the photoelectric sensor 30.
  • the photoelectric sensor 30 can recognize (detect) the presence of the substrate 1 even when the substrate 1 is made of a material that transmits the light beam 10.
  • FIG. 2 is an enlarged cross-sectional view of the left total reflection surface 2 in the substrate 1 of FIG. Accordingly, since the region on the right side of the substrate 1 in FIG. 1 is omitted in FIG. 2, a wavy line is provided on the right side in FIG.
  • the total reflection surface 2 of the substrate 1 shown in FIG. 2 forms an angle ⁇ with the main surface of the substrate 1 (surface extending in the left-right direction in FIG. 1) as shown in FIG.
  • the angle ⁇ is an angle at which the light beam 10 incident on the substrate 1 from a direction perpendicular to the main surface of the substrate 1 can be totally reflected by the total reflection surface 2 as described above.
  • positioned is the distance (distance from the left end in FIG. 2 to the right side) of the main surface direction from the outer periphery end (left end in FIG. 2) of the board
  • the total reflection surface 2 and the lower main surface in FIG. May be small (a sharp angle).
  • the substrate 1 will be chipped or cleaved starting from the outer peripheral end (the end portion of the substrate 1 having a sharp angle).
  • the angle with respect to the main surface is larger than the total reflection surface 2. It is preferable to provide an end face. Further, the shape of the end surface from the outer peripheral end to the point A may be a plane as shown in FIG.
  • the surface shape of the end surface may be a curved surface.
  • a configuration in which the end surface from the outer peripheral end to the point A shown in FIG. 2 described above is not provided (a configuration in which the outer peripheral side from the point B is the total reflection surface 2) is possible.
  • the region of 5 mm or more from the outer peripheral edge of the substrate 1 corresponds to the central portion of the main surface of the substrate 1 and is a region where a semiconductor element or the like is formed. Therefore, if the total reflection surface 2 is provided in a region of 5 mm or more from the end surface of the substrate 1, the region for forming a semiconductor element or the like on the main surface of the substrate 1 is reduced, so that the productivity of the semiconductor device is lowered. . For this reason, it is preferable to set the distance L2 to be 5 mm or less.
  • the total reflection surface 2 only needs to be formed on at least a part of the end portion of the main surface of the substrate 1. That is, the total reflection surface 2 may be formed so as to make one round of the outer peripheral portion of the main surface of the substrate 1 in the entire region whose distance from the end surface of the main surface of the substrate 1 is, for example, 0.1 mm or more and 5 mm or less. And you may form the total reflection surface 2 only in a part in the circumferential direction of the said outer peripheral part.
  • a method for manufacturing a substrate according to Embodiment 1 of the present invention will be described.
  • a step of preparing the substrate (S10) is performed. Specifically, this is achieved by using a light beam 10 (see FIG. 1) irradiated for detecting a substrate in an apparatus such as a semiconductor device manufacturing apparatus (for example, a film forming apparatus or an etching apparatus).
  • a transparent substrate to be a base for forming a transparent substrate 1 (see FIG. 1) that can be recognized.
  • the substrate prepared here is a semiconductor substrate for forming a semiconductor device such as a power device by forming a semiconductor element on one main surface of the substrate, for example, visible light (red light) or infrared light.
  • a transparent semiconductor substrate that transmits 10% or more of the light beam 10 is preferable.
  • the substrate is made of a material including at least one selected from the group consisting of SiC, GaN, sapphire, AlN, and diamond, for example.
  • the above-described substrate having a predetermined thickness and a predetermined main surface size may be purchased from the outside.
  • the Czochralski method or boat Forming an ingot made of a crystal constituting the semiconductor substrate using a method, a solution growth method, etc., and cutting the ingot into a shape as a substrate having a predetermined thickness and a predetermined main surface size using, for example, a wire saw By doing so, a substrate may be prepared.
  • a processing step (S20) is performed. Specifically, in order to make the light transmittance in at least a partial region of the end portion of the substrate prepared in the step (S10) of preparing the substrate function as a detection region, the central portion of the main surface of the substrate This is a step of performing processing for making the transmittance of the region smaller than the transmittance of the light in.
  • the light transmittance in the region of the substrate is a region other than the region of the substrate (that is, the region not subjected to processing for reducing the transmittance).
  • the processing is performed so as to be smaller than the light transmittance.
  • the processing means that the light transmittance in the region is 10% or less of the light transmittance in other regions.
  • this processing step (S20) in order to make the light transmittance in at least a part of the end portion of the main surface of the substrate smaller than the light transmittance in the central portion of the main surface of the substrate, A step of forming a total reflection surface that totally reflects light incident on at least a part of the portion is performed.
  • predetermined conditions satisfying conditions that can cause total reflection when irradiated with a light beam 10 traveling in a direction intersecting the main surface of substrate 1 (left-right direction in FIG. 1) for example, a vertical direction.
  • a total reflection surface 2 having an angle ⁇ is formed. As shown in FIG.
  • the total reflection surface 2 may be formed so that almost the entire end face of the outer peripheral portion of the substrate 1 becomes the total reflection surface 2.
  • the total reflection surface 2 and the conventional bevel cut surface 4 used conventionally may coexist in the detection region. That is, the angle formed by the total reflection surface 2 on the side on which the light beam 10 is incident (upper side in FIG. 4) and the main surface of the substrate 3 (left-right direction in FIG. 4) is an angle that satisfies the condition for total reflection of the light beam 10.
  • a normal structure, for example, a bevel cut surface 4 for suppressing chipping or cleavage of the substrate 3 may be formed on the side opposite to the side on which the light beam 10 is incident (the lower side in FIG. 4).
  • the bevel cut surface 4 has a main surface on the side where the total reflection surface 2 of the substrate 3 is formed so that the angle of the corner of the connection portion with the total reflection surface 4 is an acute angle as shown in FIG.
  • the substrate 3 is formed so as to be inclined in the opposite direction to the total reflection surface 2 so that the width of the substrate 3 becomes smaller toward the opposite main surface (back surface).
  • the total reflection surface 2 is formed to have an angle satisfying the same conditions as the total reflection surface 2 of the substrate 5 described above, and opposite to the side on which the light beam 10 is incident.
  • an end surface 6 and a normal bevel cut surface 7 that are substantially perpendicular to the main surface (left-right direction in FIG. 5) of the substrate 5 may be formed. That is, from a different point of view, the outer peripheral edge of the substrate 5 has a configuration in which the total reflection surface 2 and the bevel cut surface 7 are arranged with the end surface 6 being substantially perpendicular to the main surface. Also good.
  • the bevel cut surfaces 4 and 7 and the end surface 6 are provided below the total reflection surface 2 (opposite the side on which the light beam 10 is incident).
  • a round (surface having a curved surface) formed at the end of the substrate in FIG. 15 (left side in FIG. 15) may be formed so as to be continuous with the total reflection surface 2.
  • an arbitrary shape for suppressing cleavage and chipping of the substrate due to stress for example, can be provided under the total reflection surface 2 of each substrate.
  • the step of forming total reflection surface 2 of each substrate according to the first embodiment of the present invention described above may include, for example, a step of machining at least a part of the end portion. May include a step of laser processing at least a part thereof. For example, using a grinding wheel, a predetermined region at the end of the main surface of the substrate 1 is removed so as to satisfy an angle that satisfies the condition for total reflection of the light beam 10 irradiated from a direction substantially perpendicular to the main surface. By doing so, the total reflection surface 2 can be formed. Alternatively, the total reflection surface 2 may be formed by removing the end portion of the substrate 1 in the same manner using a laser.
  • the surface roughness of the total reflection surface 2 to be formed is reduced to such an extent that the irradiated light beam 10 can be totally reflected.
  • the surface roughness is preferably processed so that Ra is 0.5 nm or less, and more preferably Ra is 0.1 nm or less.
  • the particle size of the grindstone used in the finishing process is 100 nm or less.
  • a substrate 8 according to the second embodiment of the present invention shown in FIG. 6 has basically the same mode as the substrate 1 according to the first embodiment of the present invention shown in FIG.
  • the substrate 8 shown in FIG. 6 includes an irregular reflection surface 9 for irregularly reflecting the incident light beam 10 in the detection region, instead of the total reflection surface 2 shown in FIG. In this respect, the substrate 8 and the substrate 1 are different.
  • a light beam 10 irradiated from a region (upper side in FIG. 6) facing one main surface of the substrate 8 is transmitted to the other main surface (lower side in FIG. 6) located on the opposite side of the one main surface of the substrate 8. If this can be suppressed, the photoelectric sensor 30 positioned below the substrate 8 can recognize that the light beam 10 has been blocked by the substrate 8, and therefore the presence of the substrate 8 can be detected. Therefore, in order to suppress the transmission of the light beam 10 through the substrate 8, the incident light beam 10 may be totally reflected as in the substrate 1 shown in FIG. 1, but the diffuse reflection surface 9 as in the substrate 8 shown in FIG. The effect similar to the case where the light beam 10 is diffusely reflected can be obtained.
  • FIG. 7 is an enlarged cross-sectional view of the left irregular reflection surface 9 in the substrate 8 of FIG. Therefore, the region on the right side of the substrate 8 in FIG. 6 is not shown in FIG. Therefore, a wavy line is shown on the right side of FIG. 7, suggesting that the substrate 8 extends to the right side.
  • the irregular reflection surface 9 shown in FIG. 7 has a configuration in which processing for increasing the surface roughness is performed on the total reflection surface 2 shown in FIG. That is, similarly to FIG. 2, as shown in FIG. 7, the irregular reflection surface 9 of the substrate 8 forms an angle ⁇ with the main surface of the substrate 8 (surface extending in the left-right direction in FIG. 7).
  • to increase the surface roughness means to process the surface so as to have a surface roughness that can diffusely reflect the light beam 10 incident on the surface (to form an uneven shape). More specifically, it means that the surface is processed so that the surface roughness Ra is 0.1 ⁇ m or more.
  • the detection region which is a region subjected to processing for increasing the surface roughness in order to exhibit the function as the irregular reflection surface 9, is from the outer peripheral end (left end in FIG. 7) of the substrate 8. It is preferable that the distance in the main surface direction (from the left end to the right side in FIG. 7) is 0.1 mm to 5 mm. That is, if the irregular reflection surface 9 is from point C to point D in FIG. 7, the distance L3 in the main surface direction from the outer peripheral edge of the substrate 8 to the point C is 0.1 mm or more, and the point D from the outer peripheral edge of the substrate 8.
  • the distance L4 in the main surface direction is preferably 5 mm or less.
  • the irregular reflection surface 9 may be formed on at least a part of the end portion of the main surface of the substrate 8. That is, the irregular reflection surface 9 may be formed so as to make one round of the outer peripheral portion of the main surface of the substrate 8 in the entire region whose distance from the end surface of the main surface of the substrate 8 is, for example, 0.1 mm or more and 5 mm or less. Alternatively, the irregular reflection surface 9 may be formed only on a part of the outer peripheral portion in the circumferential direction.
  • the example which forms the irregular reflection surface 9 by raising the surface roughness of the total reflection surface 2 as shown in FIG. 7 is an example.
  • a diffuse reflection surface having a large surface roughness at the end of the main surface of the substrate 8 without once forming a total reflection surface (that is, without forming an inclined portion or the like at the end of the substrate 8). 9 may be formed.
  • a surface intersecting with one main surface (the upper main surface in FIGS. 6 and 7) and the other main surface (the lower main surface in FIGS. 6 and 7) of the substrate 8 is formed. Even in the case of formation, the angle formed between the intersecting surface and the main surface of the substrate 8 does not need to be an angle that satisfies the condition for causing the light ray 10 to undergo total reflection, such as an angle ⁇ shown in FIG.
  • the substrate according to the second embodiment of the present invention like the substrate 3 shown in FIG. 4 as described above, for example, as in the substrate 11 shown in FIG. 4 may coexist. Or, for example, like the substrate 12 shown in FIG. 9, similarly to the substrate 5 in FIG. 5 described above, a structure in which the irregular reflection surface 9, the end surface 6, and the bevel cut surface 7 coexist may be used.
  • an arbitrary shape for suppressing cleavage and chipping of the substrate due to stress for example, can be provided below the irregular reflection surface 9 of each substrate.
  • substrate which concerns on Embodiment 2 of this invention is demonstrated.
  • a transparent substrate to be used as the substrate of the semiconductor device is prepared.
  • processing is performed to make the light transmittance in at least a partial region of the end portion of the substrate smaller than the light transmittance in the central portion of the main surface of the substrate.
  • the processing step (S20) for example, as in the substrate 8 shown in FIG. 6, in the processing step (S20), light incident on at least a part of the end portion of the main surface of the substrate 8 is irregularly reflected. A step of forming the irregular reflection surface 9 is included.
  • the main surface (the upper main surface in FIG. 7) and the other main surface (the lower side in FIG. 7) of the substrate 8 are formed in order to form the irregular reflection surface 9.
  • a surface intersecting with the main surface) may be formed, and processing for increasing the surface roughness of the formed surface may be performed.
  • the angle formed by the intersecting surface with the main surface of the substrate 8 may be, for example, an angle ⁇ (see FIG. 1) that satisfies the condition that the light ray 10 incident from a direction perpendicular to the main surface is totally reflected. Any other angle can be used.
  • the irregular reflection surface 9 having a large surface roughness may be formed at the end of the main surface of the substrate 8 without forming the above-described intersecting surfaces.
  • the region having a large surface roughness for exhibiting the function as the irregular reflection surface 9 is formed in a region from 0.1 mm to 5 mm from the end surface of the main surface of the substrate 8.
  • a step of machining at least a portion of the end portion may be included, and a step of laser machining at least a portion of the end portion may be included.
  • a shape for forming the irregular reflection surface 9 as shown in the substrate 8 is processed using a grindstone, And the method of giving the process which enlarges surface roughness is used.
  • processing for increasing the surface roughness is performed by irradiating a predetermined region with laser. Specifically, it is preferable to irradiate a UV laser having a wavelength of 266 nm.
  • the irregular reflection surface 9 for example, a method described below can be used. As shown in FIG. 10, in the method, as the step of introducing impurities (S21), the introduction of impurities into the region of the substrate where the irregular reflection surface is formed, that is, at least a portion of the edge of the substrate is introduced. The process to perform is implemented.
  • the region of the substrate 8 where the irregular reflection surface is to be formed that is, the region of 0.1 mm or more and 5 mm or less from the end of the main surface of the substrate 8 (for example, the left end in the substrate 8 of FIG. 11) Ions are implanted from the surface into the substrate 8 to form crystal defects 13 constituting the substrate 8.
  • Ions are implanted from the surface into the substrate 8 to form crystal defects 13 constituting the substrate 8.
  • B boron
  • N nitrogen
  • Al aluminum
  • P phosphorus
  • the density (concentration) of impurities to be introduced is preferably 1.0E17 cm ⁇ 3 or more and 1.0E21 cm ⁇ 3 or less, and 1.0E19 cm ⁇ 3 or more and 1. More preferably, it is 0E20 cm ⁇ 3 or less.
  • the density (concentration) is in the above range, the effect of irregularly reflecting the light beam 10 incident on the region can be increased.
  • an etching step (S22) is performed as shown in FIG. Specifically, this is a step of performing a wet etching process on the surface layer of the substrate on which the ions have been implanted in the step of introducing impurities (S21).
  • the substrate 8 on which the defect 13 is formed by ion implantation is immersed in the KOH solution 14.
  • KOH is potassium hydroxide, which is a strongly alkaline substance having a strong etching property.
  • the etching rate of the main surface of the substrate 8 is locally changed (not uniform) due to the presence of the defect 13, so that irregularities are formed on the etched surface. Is done.
  • the surface roughness of the surface where the defect is formed increases.
  • the amount by which the main surface is etched is substantially the same in the region, and the surface roughness of the main surface does not change greatly.
  • the surface roughness can be increased only in the region of the main surface of the substrate 8 where ion implantation is performed and crystal defects 13 are generated. For this reason, the main surface of the ion-implanted region can be used as the irregular reflection surface.
  • a thermal diffusion method may be used instead of the above-described ion implantation method.
  • an impurity introduction step (S21) is first performed.
  • a heat treatment step (S23) is performed instead of the etching step (S22) in the ion implantation method shown in FIG.
  • a defect is formed in the region where the impurity is introduced, and as a result, irregularities are formed on the surface of the region where the impurity is introduced.
  • the ion implantation method shown in FIG. 10 may be used, but other methods may be used. Specifically, for example, the substrate and the object are overheated in a state where the object including the impurity is in contact with a region of the substrate where the impurity is to be introduced. As a result, impurities diffuse from the object into the substrate by solid diffusion.
  • a mask layer is formed so that only a region where impurities are to be introduced is exposed in the substrate, and the substrate on which the mask layer is formed is heated in a heat treatment furnace. During this heating, a gas containing an impurity to be introduced is used as an atmosphere gas in the heat treatment furnace. In this way, impurities can be introduced into a predetermined region of the substrate (region where the mask layer is not formed) by heat treatment.
  • the impurity is introduced using the above method (thermal diffusion method) and then the heat treatment step (S23) is performed, the unevenness of the region into which the impurity is introduced in the main surface of the substrate can be increased.
  • the irregular reflection surface can be formed.
  • the second embodiment of the present invention is different from the first embodiment of the present invention only in each of the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the second embodiment of the present invention are all in accordance with the first embodiment of the present invention.
  • the substrate 15 shown in FIG. 14 includes a thin film 16 used as a detection region, for example, in one main surface (the upper main surface in FIG. 14) of the substrate 15 in a region from 0.1 mm to 5 mm from the end face.
  • the thin film 16 diffusely reflects the light beam 10 incident on the main surface of the substrate 15 from the upper side of the substrate 15 in a direction substantially perpendicular to the main surface of the substrate 15.
  • a metal thin film that can reflect visible light (red light), infrared light, and the like at a high rate, such as Cr (chromium), W (tungsten), and Al (aluminum) is used. It is preferable.
  • the light incident on the detection region can be diffusely reflected by the thin film 16 as in the above-described substrate 8 according to the second embodiment of the present invention. For this reason, the light rays 10 incident on the photoelectric sensor 30 arranged on the lower side of the substrate 15 (see FIG. 14) are reduced. At this time, the photoelectric sensor 30 can detect the presence of the substrate 15 by recognizing the interruption of the light beam 10.
  • the substrate manufacturing method according to Embodiment 3 of the present invention follows the above-described procedure of the substrate manufacturing method according to Embodiment 1 of the present invention shown in FIG. However, in the processing step (S20) of FIG. 3, as the processing for making the light transmittance in at least a partial region of the end portion of the substrate smaller than the light transmittance in the central portion of the main surface of the substrate, FIG. As shown in FIG. 2, a thin film 16 is formed on one main surface of the substrate 15. Since this thin film 16 is used as an irregular reflection surface, the distance in the main surface direction from the end surface of the main surface of the substrate 15 is not less than 0.1 mm and not more than 5 mm, for example, similarly to the substrate 8 shown in FIG.
  • the material of the thin film 16 is preferably a metal thin film that can reflect visible light (red light), infrared light, and the like at a high rate, such as Cr, W, and Al.
  • the film thickness of the thin film 16 is preferably 0.05 ⁇ m or more and 1.0 ⁇ m or less, and more preferably 0.1 ⁇ m or more and 0.5 ⁇ m or less.
  • a vacuum evaporation method, CVD method, sputtering method etc. for example.
  • a substrate 11 as shown in FIG. 8 has a structure in which a thin film 16 used as a diffusely reflecting surface and a normal bevel cut surface 4 conventionally used coexist. It may be.
  • a structure in which the thin film 16 used as the irregular reflection surface, the end surface 6 and the bevel cut surface 7 coexist may be used.
  • an arbitrary shape can be provided on the lower side of the thin film 16 used as the irregular reflection surface of each substrate, for example, to suppress cleavage and chipping of the substrate due to stress.
  • the thin film 16 described above is formed as an irregular reflection surface
  • the thin film 16 may be formed to be a total reflection surface by controlling the surface state of the thin film 16 and the like.
  • the third embodiment of the present invention is different from the second embodiment of the present invention only in the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the third embodiment of the present invention are all in accordance with the second embodiment of the present invention.
  • the present invention is particularly excellent as a technique that enables a sensor to recognize the presence of a transparent substrate when a process such as manufacturing a semiconductor device is performed using the transparent substrate.

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Abstract

Provided are a substrate, the presence of which can be detected using a method similar to that used for conventional Si substrates even if the substrate is transparent, and a method for manufacturing the substrate.  A beam (10) entering the end portion of a transparent substrate (1) does not pass through the substrate (1), unlike a beam (10) that enters the center portion of the substrate (1), and is totally reflected by a totally reflecting surface (2) in a detection region present at least on a part of the end portion of the substrate (1).  A photoelectric sensor (30) detects the presence of the substrate (1) by recognizing a reduction in the proportion of the beam (10) passing through the end portion of the substrate (1).

Description

基板および基板の製造方法Substrate and substrate manufacturing method
 本発明は、基板および基板の製造方法に関するものであり、より特定的には、透明であってもセンサによりその存在を認識することが可能な基板、および当該基板の製造方法に関するものである。 The present invention relates to a substrate and a method for manufacturing the substrate, and more specifically to a substrate that can be recognized by a sensor even if it is transparent, and a method for manufacturing the substrate.
 半導体基板の主表面上にたとえばMOSFET(Metal Oxide Semiconductor Field Effect Transistor)などの半導体素子を形成する場合、通常は主表面上において、半導体基板の外周から一定の距離(通常は5mm程度)以上離れた、中心部の領域に半導体素子を形成する。なお、ここで主表面とは、表面のうち最も面積の大きい面をいうこととする。したがって、半導体基板の外周から一定の距離以内の領域には半導体素子を形成しない。このような主表面の外周に近い、すなわち端部の領域に形成した半導体素子は、その電気的特性等の信頼性が低下することがあるためである。 When a semiconductor element such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is formed on the main surface of the semiconductor substrate, it is usually separated from the outer periphery of the semiconductor substrate by a certain distance (usually about 5 mm) or more on the main surface. A semiconductor element is formed in the central region. Here, the main surface refers to the surface having the largest area among the surfaces. Therefore, no semiconductor element is formed in a region within a certain distance from the outer periphery of the semiconductor substrate. This is because such a semiconductor element formed near the outer periphery of the main surface, that is, in the end region, may have reduced reliability such as electrical characteristics.
 半導体素子を形成しない、上述した半導体基板の主表面の外周近傍の領域、すなわち端部には、たとえばIDマークを形成することが多い。当該IDマークは、半導体基板の主表面上に半導体素子が多数形成された半導体装置を製造ための工程を行なう際に、一貫した生産管理を行なうために用いる。すなわち、半導体基板の主表面の端部に、各半導体基板を識別するための数字や文字、バーコードなどをIDマークとして配置する場合がある。 In many cases, for example, an ID mark is formed in a region near the outer periphery of the main surface of the semiconductor substrate, that is, an end portion where no semiconductor element is formed. The ID mark is used for consistent production management when performing a process for manufacturing a semiconductor device in which a large number of semiconductor elements are formed on the main surface of the semiconductor substrate. In other words, numbers, characters, barcodes, etc. for identifying each semiconductor substrate may be arranged as ID marks at the end of the main surface of the semiconductor substrate.
 IDマークとしては従来より、たとえば半導体基板の主表面の端部にドット(凹部)を多数形成したものを用いてきた。これは、たとえばレーザビームを半導体基板の主表面上に照射させて半導体基板を構成する材質を部分的に除去させることにより、当該半導体基板の主表面の端部の領域に、当該半導体基板を識別するためのドットの集合体を配置したものである。たとえば特開2004-200635号公報(以下、「特許文献1」という)には、形成した当該ドットが、後工程である化学的機械的研磨工程(CMP工程)により研磨されて平坦化され、当該ドットの存在をセンサで認識することが困難になることを抑制するため、CMP工程を行なう研磨布が接触しない窪みを形成し、当該窪みの底面上にドットを形成した半導体ウェハが開示されている。 As an ID mark, for example, a mark in which a large number of dots (concave portions) are formed at the end of the main surface of a semiconductor substrate has been used. For example, by irradiating the main surface of the semiconductor substrate with a laser beam to partially remove the material constituting the semiconductor substrate, the semiconductor substrate is identified in the end region of the main surface of the semiconductor substrate. This is an arrangement of a set of dots for the purpose. For example, in Japanese Patent Application Laid-Open No. 2004-200355 (hereinafter referred to as “Patent Document 1”), the formed dots are polished and flattened by a chemical mechanical polishing process (CMP process) which is a subsequent process. In order to suppress the difficulty of recognizing the presence of dots by a sensor, a semiconductor wafer is disclosed in which a recess that does not come into contact with a polishing cloth for performing a CMP process is formed and dots are formed on the bottom surface of the recess. .
特開2004-200635号公報Japanese Patent Laid-Open No. 2004-200355
 たとえば特許文献1に開示されているように、これまで基板の主表面の端部の形状としては、チッピングを抑制するために主表面に対して一定の傾き角度を有する端面となるよう加工されたベベルカットが主に用いられてきた。これは具体的には、基板の一方の主表面と、当該一方の主表面に対向する基板の他方の主表面とのそれぞれに交差するように、両主表面と所定角度をなす面を、基板の端部に形成して当該基板の端面としたものである。このベベルカットの他にも、たとえば応力が加わることにより、半導体基板やガラス基板などの端部から、結晶格子に沿った方向へのへき開(割れ)やチッピングが発生することを抑制するために、基板の主表面の端部に対して、たとえば平面状や球面状の端面を形成する加工を行なうこともある。たとえば図15は、基板の端部にラウンドを施した状態を示す概略図である。図15に示す基板20は、主表面の端部にラウンドと呼ばれる曲面状の特殊端部加工が施されている。すなわち基板20の一方の主表面(図15における上側の面)および一方の主表面の反対側に位置する他方の主表面(図15における下側の面)とを結ぶ曲面(図15における左側の半円部分である端部)を設け、当該曲面を基板の端面としたものである。 For example, as disclosed in Patent Document 1, the shape of the end portion of the main surface of the substrate has been processed so as to be an end surface having a certain inclination angle with respect to the main surface so as to suppress chipping. Bevel cut has been mainly used. Specifically, a surface that forms a predetermined angle with both main surfaces so as to intersect each of one main surface of the substrate and the other main surface of the substrate facing the one main surface, The end surface of the substrate is formed at the end of the substrate. In addition to this bevel cut, in order to suppress the occurrence of cleavage (chipping) or chipping in the direction along the crystal lattice from the end of a semiconductor substrate or glass substrate, for example, by applying stress, For example, the end of the main surface of the substrate may be processed to form a planar or spherical end surface. For example, FIG. 15 is a schematic view showing a state in which a round is applied to the end portion of the substrate. A substrate 20 shown in FIG. 15 has a special end processing of a curved surface called a round at the end of the main surface. That is, a curved surface (on the left side in FIG. 15) connecting one main surface (the upper surface in FIG. 15) of the substrate 20 and the other main surface (the lower surface in FIG. 15) located on the opposite side of the one main surface. An end portion which is a semicircular portion) is provided, and the curved surface is used as an end surface of the substrate.
 ところで、半導体装置を生産する際には、当該生産に用いる製造装置において半導体基板のハンドリングや搬送を行なう過程で、半導体基板の存在をセンサにより認識し、同時にその半導体基板のIDマークを認識し、それらを照合することにより当該半導体基板の管理や自動シーケンスの実行を行なう方法が一般的に行なわれている。ここで、半導体基板の存在を認識する工程では、一般的に赤色または赤外LED(発光ダイオード)あるいはLD(レーザダイオード)が光源として用いられる。これは、従来半導体基板として主に用いられていたシリコン(Si)は赤色光または赤外光を吸収するため、これらの光を用いてシリコンからなる半導体基板を容易に検出することができるためである。 By the way, when producing a semiconductor device, in the process of handling and transporting the semiconductor substrate in the manufacturing apparatus used for the production, the presence of the semiconductor substrate is recognized by the sensor, and at the same time the ID mark of the semiconductor substrate is recognized, A method of managing the semiconductor substrate and executing an automatic sequence by comparing them is generally performed. Here, in the step of recognizing the presence of the semiconductor substrate, a red or infrared LED (light emitting diode) or LD (laser diode) is generally used as a light source. This is because silicon (Si), which has been mainly used as a conventional semiconductor substrate, absorbs red light or infrared light, so that it is possible to easily detect a semiconductor substrate made of silicon using these lights. is there.
 たとえば図15に示すように、基板20(たとえばSiなどの半導体基板)の一方の主表面に対向する領域から、当該一方の主表面(図15における上側の面)に対して赤色光または赤外光を照射する。ここで基板20の一方の主表面と反対側の主表面(図15における下側の面)に対向する領域に、入射される赤色光などの光線10を認識するための光電センサ30を設置しておく。すると基板20が存在しない場合は、図15に示すように基板20の一方の主表面の上方から照射される光線10は、光電センサ30に入射する。このとき、光電センサ30が光線10を検出することによって基板20が存在しないと認識できる。しかしここにたとえばSiなど、赤色光または赤外光を吸収する材料からなる基板20が存在すると、図15の上方から照射される光線10は基板20の主表面上にてその多くが吸収・反射される。このため図15の下方に存在する光電センサ30に到達する光線10の光量が、基板20が存在しない場合に比べて少なくなる。つまり、図15において基板20の下方に存在する光電センサ30が受光する光線10の強度が、基板20が存在しない場合に比べて弱くなれば、光電センサ30により、基板20の存在を検出できる。 For example, as shown in FIG. 15, from a region facing one main surface of a substrate 20 (for example, a semiconductor substrate such as Si), red light or infrared light with respect to the one main surface (upper surface in FIG. 15). Irradiate light. Here, a photoelectric sensor 30 for recognizing the light beam 10 such as incident red light is installed in a region facing the main surface opposite to the one main surface of the substrate 20 (the lower surface in FIG. 15). Keep it. Then, when the substrate 20 does not exist, the light beam 10 irradiated from above one main surface of the substrate 20 enters the photoelectric sensor 30 as shown in FIG. At this time, it can be recognized that the substrate 20 does not exist when the photoelectric sensor 30 detects the light beam 10. However, if there is a substrate 20 made of a material that absorbs red light or infrared light such as Si, for example, most of the light rays 10 irradiated from above in FIG. 15 are absorbed and reflected on the main surface of the substrate 20. Is done. For this reason, the light quantity of the light beam 10 reaching the photoelectric sensor 30 existing in the lower part of FIG. 15 is smaller than that when the substrate 20 is not present. That is, if the intensity of the light beam 10 received by the photoelectric sensor 30 existing below the substrate 20 in FIG. 15 is weaker than that when the substrate 20 is not present, the photoelectric sensor 30 can detect the presence of the substrate 20.
 近年、Siに代わって、炭化珪素(SiC)などの化合物半導体を用いた半導体素子(半導体装置)が、高周波パワーデバイスや、耐熱・耐放射線デバイスを実現するための材料として注目されている。これは、SiCやGaNなどの化合物半導体はSiと比べて、バンドギャップ(禁止帯幅)が広く、絶縁破壊電界強度が大きいため、当該化合物半導体を用いた半導体装置は、たとえばSiを用いた半導体装置に比べてスイッチング特性に優れ、耐電圧が大きくなることなどによる。しかし、このような化合物半導体からなる基板のうち、SiCやGaNなどからなる基板は透明であるため、当該基板に照射した光は、基板により反射されることが少なく、その多くは基板を透過する。このため、仮に図15における基板20が上述のような透明な基板であるとすれば、図15に示すように赤色光または赤外光などの光線10を基板20に照射しても、たとえばSiからなる基板に光線10を照射した場合に比べて、光線10は基板20にて反射される割合が少なくなる(つまり基板20を透過する光線10の割合が大きくなる)。このため光電センサ30は、光線10の強度変化により基板20の存在を認識することが困難となる。 In recent years, a semiconductor element (semiconductor device) using a compound semiconductor such as silicon carbide (SiC) instead of Si has been attracting attention as a material for realizing a high-frequency power device and a heat and radiation resistant device. This is because a compound semiconductor such as SiC or GaN has a wider band gap (forbidden band width) and a higher dielectric breakdown electric field strength than Si, and a semiconductor device using the compound semiconductor is, for example, a semiconductor using Si. This is because it has superior switching characteristics and a higher withstand voltage than devices. However, among substrates made of such compound semiconductors, substrates made of SiC, GaN, or the like are transparent, so that light irradiated to the substrate is less likely to be reflected by the substrate, and most of the light passes through the substrate. . Therefore, if the substrate 20 in FIG. 15 is a transparent substrate as described above, even if the substrate 20 is irradiated with light rays 10 such as red light or infrared light as shown in FIG. Compared with the case where the light beam 10 is applied to the substrate made of the above, the ratio of the light beam 10 reflected by the substrate 20 is reduced (that is, the ratio of the light beam 10 transmitted through the substrate 20 is increased). For this reason, it becomes difficult for the photoelectric sensor 30 to recognize the presence of the substrate 20 due to the intensity change of the light beam 10.
 ここで、上述した化合物半導体などからなる透明基板を用いた半導体装置の製造工程では、従来のSi基板を用いた半導体装置の製造工程と類似する工程もあるため、従来のSi基板を用いた半導体装置の製造に用いていた製造装置を流用することが考えられる。しかし、上述のようにSi基板の存在を検出する従来の方法では、透明基板の存在を正確に検出することが難しい。このため、従来のSi基板を用いた半導体装置の生産に用いていた製造装置を、上述した透明基板を用いた半導体装置の製造にそのまま流用することは困難であった。また、透明基板の存在を検出するために従来と異なる検出方法を採用しようとすると、製造装置の大幅な改造が必要となるため、結果的に製造装置のコストの増大などの問題を招くことになる。 Here, in the manufacturing process of the semiconductor device using the transparent substrate made of the compound semiconductor described above, there is a process similar to the manufacturing process of the semiconductor device using the conventional Si substrate. Therefore, the semiconductor using the conventional Si substrate is used. It is conceivable to use the manufacturing apparatus used for manufacturing the apparatus. However, with the conventional method for detecting the presence of the Si substrate as described above, it is difficult to accurately detect the presence of the transparent substrate. For this reason, it is difficult to divert the manufacturing apparatus used for the production of the semiconductor device using the conventional Si substrate as it is to the manufacture of the semiconductor device using the transparent substrate. Further, if a detection method different from the conventional one is used to detect the presence of the transparent substrate, a significant modification of the manufacturing apparatus is required, resulting in problems such as an increase in the cost of the manufacturing apparatus. Become.
 本発明は、上述した問題に鑑みなされたものであり、その目的は、透明であっても従来のSi基板と同様の手法により存在を検出することが可能な基板、および当該基板の製造方法を提供することである。 The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a substrate that can be detected by the same technique as a conventional Si substrate even if it is transparent, and a method for manufacturing the substrate. Is to provide.
 本発明に係る基板は、透明な基板であり、基板の端部の少なくとも一部に形成され、基板の中央部における光の透過率よりも小さい光の透過率を有する検出領域を備える基板である。 The substrate according to the present invention is a transparent substrate, and is a substrate provided with a detection region which is formed on at least a part of the end portion of the substrate and has a light transmittance smaller than the light transmittance at the central portion of the substrate. .
 ここで透明な基板とは、所定の波長の光(たとえば可視光(赤色光)や赤外光など)の当該基板における吸収率が低い(透過率が高い)基板を言い、たとえば所定の波長の光の吸収率が0%を超え90%以下である基板を言う。また、異なる観点から言えば、たとえば可視光について透明な基板とは、基板の一方の主表面に対向する領域から、基板の一方の主表面の反対側に位置する他方の主表面に対向する領域を、当該基板を介して目視することが可能な基板を意味する。基板の主表面のうち一部の領域(ここでは端部)を検出領域とし、検出領域において、基板の一方の主表面に対向する領域から、当該主表面の反対側に位置する他方の主表面に対向する領域へ光が透過する割合(透過率)を、基板の主表面のうち検出領域以外の領域(ここでは中央部)における同様の透過率よりも小さくする。このようにすれば、光の透過を感知するセンサ(たとえば光電センサ)は、検出領域において、当該基板の主表面に入射された光が検出領域以外の領域と比べてより遮断される(透過しなくなる)ことを認識することができる。この結果、センサは当該透明な基板の存在を認識(検出)することができる。このため、従来のSi基板の検出装置を上記基板の検出に流用することができる。したがって、従来のSi基板を用いた半導体装置の製造工程において用いていた製造装置を、上述した透明基板を用いた半導体装置の製造工程に流用することができる。なお、上述のように基板の端部には通常半導体素子などは形成されないため、基板の端部に上記のような検出領域を形成しても、基板から得られる素子の数が減る(素子の製造効率が低下する)可能性は少ない。 Here, a transparent substrate refers to a substrate having a low absorption rate (high transmittance) of light having a predetermined wavelength (for example, visible light (red light) or infrared light), for example, having a predetermined wavelength. A substrate whose light absorption rate is more than 0% and 90% or less. From a different point of view, for example, a substrate transparent to visible light is a region facing one main surface of the substrate and a region facing the other main surface located on the opposite side of the one main surface of the substrate. Means a substrate that can be visually observed through the substrate. A part of the main surface of the substrate (here, the end portion) is used as a detection region, and the other main surface located on the opposite side of the main surface from the region facing the one main surface of the substrate in the detection region. The ratio (transmittance) at which light is transmitted to the region facing the substrate is made smaller than the similar transmittance in the region other than the detection region (here, the central portion) on the main surface of the substrate. In this way, in a sensor (for example, a photoelectric sensor) that senses the transmission of light, light incident on the main surface of the substrate is more blocked (transmitted) in the detection region than in a region other than the detection region. Can be recognized. As a result, the sensor can recognize (detect) the presence of the transparent substrate. For this reason, the conventional Si substrate detection apparatus can be used for the detection of the substrate. Therefore, the manufacturing apparatus used in the manufacturing process of the semiconductor device using the conventional Si substrate can be used for the manufacturing process of the semiconductor device using the transparent substrate described above. As described above, since the semiconductor element or the like is usually not formed at the end of the substrate, the number of elements obtained from the substrate is reduced even if the detection region as described above is formed at the end of the substrate (elements of the element). There is little possibility that production efficiency will decrease.
 本発明に係る基板において、上述した検出領域は、検出領域に入射する光を全反射する全反射面を含むことが好ましい。検出領域に入射する光を全反射させれば、検出領域に入射する光はほぼすべて、光が入射した検出領域の表面上にて反射される。このため検出領域に入射する光は、検出領域から基板の内部に侵入し、基板の裏面(光が入射した側と反対側の主表面)から基板の外部に透過することはほとんどない。以上のように、基板において、基板の主表面に交差する方向に進行する光が遮断されるため、光の透過を感知するセンサは、基板の存在を認識(検出)することができる。 In the substrate according to the present invention, the detection region described above preferably includes a total reflection surface that totally reflects light incident on the detection region. If the light incident on the detection region is totally reflected, almost all the light incident on the detection region is reflected on the surface of the detection region where the light is incident. For this reason, the light incident on the detection region enters the inside of the substrate from the detection region, and hardly transmits to the outside of the substrate from the back surface (the main surface opposite to the side on which the light is incident). As described above, since light traveling in the direction intersecting the main surface of the substrate is blocked in the substrate, the sensor that senses transmission of light can recognize (detect) the presence of the substrate.
 なお、本発明に係る基板において、上述した検出領域は、検出領域に入射する光を乱反射する乱反射面を含んでいてもよい。検出領域に入射する光を乱反射させれば、検出領域に入射する光の大部分は、光が入射した検出領域の表面上にて反射される。このため上述した全反射面を含んでいる場合と同様に、検出領域に入射する光は、その多くが基板の存在により反射されるため、光電センサは、基板の存在を認識(検出)することができる。 In the substrate according to the present invention, the detection region described above may include an irregular reflection surface that irregularly reflects light incident on the detection region. If the light incident on the detection region is diffusely reflected, most of the light incident on the detection region is reflected on the surface of the detection region where the light is incident. For this reason, as in the case of including the total reflection surface described above, most of the light incident on the detection region is reflected by the presence of the substrate, so that the photoelectric sensor recognizes (detects) the presence of the substrate. Can do.
 本発明に係る基板は、SiC、GaN(窒化ガリウム)、サファイア、AlN(窒化アルミニウム)、ダイアモンドからなる群から選択された少なくとも1種を含むことが好ましい。これらはいずれも透明な基板であるため、これらの基板を用いて半導体装置を形成する際に、上述したように光の透過率を小さくした検出領域を備えることにより、センサによって当該基板の存在を容易に検出することができるようになる。 The substrate according to the present invention preferably contains at least one selected from the group consisting of SiC, GaN (gallium nitride), sapphire, AlN (aluminum nitride), and diamond. Since these are transparent substrates, when a semiconductor device is formed using these substrates, the presence of the substrate is detected by a sensor by providing a detection region with reduced light transmittance as described above. It can be easily detected.
 次に、本発明に係る基板の製造方法は、透明な基板を準備する工程と、基板の端部の少なくとも一部における光の透過率を、基板の中央部における光の透過率よりも小さくする加工を行なう工程とを備える。上述のように、透明な基板においては通常、その一方の主表面に入射した、可視光(たとえば赤色光)や赤外光などの光は、その多くが当該基板の内部を通過して、一方の主表面と反対側の主表面(裏面)から出射する。このため透明な基板は、光電センサなどのセンサを用いてその存在を検出することが困難である。これを回避するため、透明な基板を形成する工程の中で、上述したように基板の一部に、入射された光の透過率を小さくした領域(検出領域)を形成する工程を備えるようにする。なお、ここで基板の一部に入射された光の透過率を小さくするとは、具体的には、基板のうち当該領域における光の透過率が、基板のうち当該領域以外の(すなわち透過率を小さくする加工を施していない領域の)光の透過率の10%以下となるように加工を行なうこととする。 Next, in the method for manufacturing a substrate according to the present invention, the step of preparing a transparent substrate and the light transmittance in at least a part of the end portion of the substrate are made smaller than the light transmittance in the central portion of the substrate. And a process of performing processing. As described above, in a transparent substrate, light such as visible light (for example, red light) or infrared light that is incident on one main surface usually passes through the inside of the substrate. The light is emitted from the main surface (back surface) opposite to the main surface. For this reason, it is difficult to detect the presence of a transparent substrate using a sensor such as a photoelectric sensor. In order to avoid this, in the process of forming a transparent substrate, as described above, a process of forming a region (detection region) in which the transmittance of incident light is reduced is provided on a part of the substrate. To do. Note that, here, specifically, reducing the transmittance of light incident on a part of a substrate means that the transmittance of light in the region of the substrate is other than the region of the substrate (that is, the transmittance is reduced). The processing is performed so that the light transmittance is 10% or less (in the region not processed to be reduced).
 このようにすれば、形成される基板は、たとえ透明であっても、一部の領域(検出領域)において入射した光の透過率が相対的に小さくなる。このため、検出領域を介して、当該基板の内部を通過して基板の外部に透過する光が少なくなったことをセンサが認識できる。そのため、当該センサは透明な基板の存在を検出することができる。 In this way, even if the substrate to be formed is transparent, the transmittance of incident light in a part of the region (detection region) becomes relatively small. For this reason, the sensor can recognize that the amount of light passing through the inside of the substrate and transmitting to the outside of the substrate is reduced through the detection region. Therefore, the sensor can detect the presence of a transparent substrate.
 上記本発明に係る基板の製造方法において、上述した加工を行なう工程には、端部の少なくとも一部に入射する光を全反射する全反射面を形成する工程を含むことが好ましい。このように全反射面を形成することで、上述した検出領域において入射光を全反射させれば、検出領域に入射した光は基板を透過しなくなる。このため、センサは検出領域における光の透過率の変化から、基板の存在を検出することができる。上述したように全反射面を形成する工程を含む基板の製造方法を用いれば、センサにより(光の透過率の変化を検出することで)基板の存在を容易に検出できる透明な基板を形成することができる。 In the substrate manufacturing method according to the present invention, it is preferable that the step of performing the above-described processing includes a step of forming a total reflection surface that totally reflects light incident on at least a part of the end portion. By forming the total reflection surface in this way, if the incident light is totally reflected in the detection region described above, the light incident on the detection region does not pass through the substrate. Therefore, the sensor can detect the presence of the substrate from the change in light transmittance in the detection region. If the substrate manufacturing method including the step of forming the total reflection surface as described above is used, a transparent substrate that can easily detect the presence of the substrate (by detecting a change in light transmittance) is formed by a sensor. be able to.
 なお、上述した全反射面を形成する工程には、端部の少なくとも一部を機械加工する工程を含むことが好ましい。または、上述した全反射面を形成する工程には、端部の少なくとも一部をレーザ加工する工程を含んでもよい。これらの加工法を用いれば、基板の表面上の任意の領域を、(上記全反射面となるように)任意の形状へと容易に加工することができる。したがって、これらの加工法を用いることにより、容易に全反射面を形成することができるため、基板の一方の主表面から入射した光が基板の外部へ透過する割合(透過率)を小さくする検出領域を容易に形成することができる。 In addition, it is preferable that the process of forming the total reflection surface described above includes a process of machining at least a part of the end. Alternatively, the step of forming the total reflection surface described above may include a step of laser processing at least a part of the end portion. If these processing methods are used, an arbitrary region on the surface of the substrate can be easily processed into an arbitrary shape (so as to be the total reflection surface). Therefore, by using these processing methods, it is possible to easily form a total reflection surface, so that detection of reducing the ratio (transmittance) of light incident from one main surface of the substrate to the outside of the substrate is reduced. The region can be easily formed.
 なお、本発明に係る基板の製造方法において、上述した加工を行なう工程には、端部の少なくとも一部に入射する光を乱反射する乱反射面を形成する工程を含んでいてもよい。乱反射面についても全反射面と同様に、基板の端部の一部(検出領域)に入射した光を基板の当該乱反射面にて反射するので、当該光が基板の内部を通過して裏面側へ透過することを抑制する。このため、乱反射面を形成した場合についても、全反射面を形成した場合と同様に、センサによって基板の存在を容易に検出することができる。 In the substrate manufacturing method according to the present invention, the step of performing the above-described processing may include a step of forming an irregular reflection surface that irregularly reflects light incident on at least a part of the end portion. Similarly to the total reflection surface, the irregular reflection surface reflects light incident on a part of the end portion (detection region) of the substrate by the irregular reflection surface of the substrate, so that the light passes through the substrate and is on the back side. Permeation to the For this reason, even when the irregular reflection surface is formed, the presence of the substrate can be easily detected by the sensor as in the case where the total reflection surface is formed.
 上述した乱反射面を形成する工程についても、上述した全反射面を形成する工程と同様に、端部の少なくとも一部を機械加工する工程を含むことが好ましい。または、上述した乱反射面を形成する工程には、端部の少なくとも一部をレーザ加工する工程を含んでもよい。これらの加工法を用いれば、基板の表面上の任意の領域を、乱反射面となるような任意の形状へと容易に加工することができる。したがって、これらの加工法を用いることにより、容易に乱反射面を形成することができる。このため、基板の主表面から入射した光の透過率を小さくする検出領域を容易に形成することができる。 It is preferable that the step of forming the irregular reflection surface described above also includes a step of machining at least a part of the end portion as in the step of forming the total reflection surface described above. Alternatively, the step of forming the irregular reflection surface described above may include a step of laser processing at least a part of the end portion. If these processing methods are used, an arbitrary region on the surface of the substrate can be easily processed into an arbitrary shape that becomes a diffusely reflecting surface. Therefore, the irregular reflection surface can be easily formed by using these processing methods. For this reason, it is possible to easily form a detection region that reduces the transmittance of light incident from the main surface of the substrate.
 また、本発明に係る基板の製造方法において、乱反射面を形成する工程には、端部の少なくとも一部に不純物の導入を行なう工程と、不純物を導入した領域の表面の面粗度を上げる工程とを含んでいてもよい。たとえば、表面の面粗度を上げる工程は、不純物の導入を行なった領域の表面層をエッチングする工程、または不純物の導入を行なった領域の表面層を熱処理する工程を含んでいてもよい。エッチングや熱処理を行なうことにより、不純物の導入を行なった領域の表面に凹凸部を形成し、面粗度を上げることができる。したがって、当該領域の面粗度が上がることにより、当該領域を乱反射面とすることができる。このため、上述した加工方法を用いることにより、容易に検出領域となるべき乱反射面を形成することができる。この結果、基板の主表面から入射した光の透過率を小さくする検出領域を容易に形成することができる。 In the method for manufacturing a substrate according to the present invention, the step of forming the irregular reflection surface includes a step of introducing an impurity into at least a part of the end portion, and a step of increasing the surface roughness of the surface of the region into which the impurity is introduced. And may be included. For example, the step of increasing the surface roughness of the surface may include a step of etching the surface layer in the region where the impurity is introduced, or a step of heat treating the surface layer in the region where the impurity is introduced. By performing etching or heat treatment, an uneven portion can be formed on the surface of the region where the impurity is introduced, and the surface roughness can be increased. Therefore, when the surface roughness of the region increases, the region can be a diffuse reflection surface. For this reason, the irregular reflection surface which should become a detection area | region can be easily formed by using the processing method mentioned above. As a result, it is possible to easily form a detection region that reduces the transmittance of light incident from the main surface of the substrate.
 さらに、本発明に係る基板の製造方法において、乱反射面を形成する工程には、端部の少なくとも一部に薄膜を成膜する工程を含むことが好ましい。つまり、上述したように基板の主表面の所定領域の面粗度を上げることにより、当該領域を乱反射面とする代わりに、乱反射面として用いることのできる薄膜を基板の主表面上に形成してもよい。このように形成した薄膜からなる乱反射面についても、面粗度を上げることにより形成した乱反射面と同様の効果を奏することができる。また、上記本発明に係る基板の製造方法において、全反射面を形成する工程が、端部の少なくとも一部に薄膜を成膜する工程を含んでいてもよい。薄膜としては、表面が全反射面となるような任意の薄膜を用いることができる。この場合も、機械加工などにより全反射面を形成する場合と同様の効果を得ることができる。 Furthermore, in the method for manufacturing a substrate according to the present invention, it is preferable that the step of forming the irregular reflection surface includes a step of forming a thin film on at least a part of the end portion. That is, by increasing the surface roughness of a predetermined region of the main surface of the substrate as described above, a thin film that can be used as the irregular reflection surface is formed on the main surface of the substrate instead of making the region an irregular reflection surface. Also good. An irregular reflection surface made of a thin film formed in this way can also exhibit the same effects as the irregular reflection surface formed by increasing the surface roughness. In the method for manufacturing a substrate according to the present invention, the step of forming the total reflection surface may include a step of forming a thin film on at least a part of the end portion. As the thin film, any thin film whose surface is a total reflection surface can be used. In this case as well, the same effect as when the total reflection surface is formed by machining or the like can be obtained.
 本発明によれば、透明であってもセンサによりその存在を認識することが可能な基板、および当該基板の製造方法を提供することができる。 According to the present invention, it is possible to provide a substrate that can be recognized by a sensor even if it is transparent, and a method for manufacturing the substrate.
本発明の実施の形態1に係る基板の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the board | substrate which concerns on Embodiment 1 of this invention. 本発明の実施の形態1に係る基板の全反射面の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the total reflection surface of the board | substrate which concerns on Embodiment 1 of this invention. 本発明の実施の形態1に係る基板の製造方法を示すフローチャートである。It is a flowchart which shows the manufacturing method of the board | substrate which concerns on Embodiment 1 of this invention. 本発明の実施の形態1に係る、検出領域における基板の態様の変形例を示す断面図である。It is sectional drawing which shows the modification of the aspect of the board | substrate in a detection area based on Embodiment 1 of this invention. 本発明の実施の形態1に係る、検出領域における基板の態様の別の変形例を示す断面図である。It is sectional drawing which shows another modification of the aspect of the board | substrate in a detection area based on Embodiment 1 of this invention. 本発明の実施の形態2に係る基板の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the board | substrate which concerns on Embodiment 2 of this invention. 本発明の実施の形態2に係る基板の乱反射面の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the irregular reflection surface of the board | substrate which concerns on Embodiment 2 of this invention. 本発明の実施の形態2に係る、検出領域における基板の態様の変形例を示す断面図である。It is sectional drawing which shows the modification of the aspect of the board | substrate in a detection area based on Embodiment 2 of this invention. 本発明の実施の形態2に係る、検出領域における基板の態様の別の変形例を示す断面図である。It is sectional drawing which shows another modification of the aspect of the board | substrate in a detection area based on Embodiment 2 of this invention. 本発明の実施の形態2に係る乱反射面を形成する別の方法を示すフローチャートである。It is a flowchart which shows another method of forming the irregular reflection surface which concerns on Embodiment 2 of this invention. 図10のフローチャートの不純物を導入する工程(S21)の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the process (S21) which introduce | transduces the impurity of the flowchart of FIG. 図10のフローチャートのエッチングする工程(S22)の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the process (S22) of etching of the flowchart of FIG. 熱拡散法を用いて本発明の実施の形態2における乱反射面を形成する方法を示すフローチャートである。It is a flowchart which shows the method of forming the irregular reflection surface in Embodiment 2 of this invention using a thermal diffusion method. 本発明の実施の形態3に係る基板の態様を示す概略断面図である。It is a schematic sectional drawing which shows the aspect of the board | substrate which concerns on Embodiment 3 of this invention. 基板の端部にラウンドを施した状態を示す概略図である。It is the schematic which shows the state which rounded the edge part of the board | substrate.
 以下、図面を参照しながら、本発明の実施の形態が説明される。なお、各実施の形態において、同一の機能を果たす部位には同一の参照符号が付されており、その説明は、特に必要がなければ、繰り返さない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.
 (実施の形態1)
 図1を参照して、本発明の実施の形態1に係る基板1は所定厚み(図1の上下方向)を有する、たとえば高周波パワーデバイスや、耐熱・耐放射線デバイスなどの半導体装置に用いる透明の基板である。また図1においては説明の便宜上、基板1は台形状に描写しているが、実際は厚み(図1の上下方向)がたとえば1mm前後、径(図1の左右方向)がたとえば2インチ前後の平板状をなしている。このため図1においては二重波線を用いて、左右方向の幅を省略していることを表わしている。
(Embodiment 1)
Referring to FIG. 1, a substrate 1 according to Embodiment 1 of the present invention has a predetermined thickness (vertical direction in FIG. 1), and is a transparent material used for a semiconductor device such as a high frequency power device or a heat / radiation resistant device. It is a substrate. In FIG. 1, for convenience of explanation, the substrate 1 is depicted in a trapezoidal shape, but in actuality, a flat plate having a thickness (vertical direction in FIG. 1) of, for example, about 1 mm and a diameter (horizontal direction of FIG. It has a shape. For this reason, in FIG. 1, a double wavy line is used to indicate that the width in the left-right direction is omitted.
 図1における基板1は、上述したように透明な基板であるが、具体的にはたとえばSiC、GaN、サファイア、AlN、ダイアモンドからなる群から選択された少なくとも1種を含む材質で構成されることが好ましい。これらの材質にて構成された基板1は、化合物半導体を用いたパワーデバイスなどの半導体素子(半導体装置)の基板として利用され得る。 The substrate 1 in FIG. 1 is a transparent substrate as described above. Specifically, the substrate 1 is made of a material containing at least one selected from the group consisting of SiC, GaN, sapphire, AlN, diamond, for example. Is preferred. The substrate 1 made of these materials can be used as a substrate for a semiconductor element (semiconductor device) such as a power device using a compound semiconductor.
 図1の基板1は透明なため、基板1の上方の主表面側から下方の主表面(裏面)側へ、当該主表面に交差する(ほぼ垂直な)方向に透過する光線10(光)は、図1の中央部分(図1の左右方向の中央部分)においては高い割合で基板1の内部を通過し、下方の主表面から基板1の外部に出射する。ここで光線10は、たとえば赤色光などの可視光でもよいし、赤外光などの非可視光でもよい。ただし特に、上述した各種の材質からなる基板1を用いた場合は、当該基板1は200nm以上800nm以下の波長の光に対して透明であることが好ましい。なお、当該基板1は300nm以上700nm以下の波長の光に対して透明であることが特に好ましい。光線10として上述した波長の光を用いれば、精度
の高いセンサとして作動させることができる。
Since the substrate 1 in FIG. 1 is transparent, a light beam 10 (light) transmitted from the upper main surface side of the substrate 1 to the lower main surface (back surface) side in a direction intersecting (substantially perpendicular) the main surface. 1 passes through the inside of the substrate 1 at a high rate in the central portion (the central portion in the left-right direction in FIG. 1), and exits from the lower main surface to the outside of the substrate 1. Here, the light beam 10 may be visible light such as red light, or may be non-visible light such as infrared light. However, in particular, when the substrate 1 made of the various materials described above is used, the substrate 1 is preferably transparent to light having a wavelength of 200 nm to 800 nm. The substrate 1 is particularly preferably transparent to light having a wavelength of 300 nm to 700 nm. If light having the above-described wavelength is used as the light beam 10, it can be operated as a highly accurate sensor.
 これに対し、基板1の端部(図1における基板1の左右側)に入射する光線10は、たとえ基板1の中央部分に入射する光線10と同一波長、同一強度であったとしても、基板1の中央部分に入射する光線10のように基板1を透過せず、図1に示すように基板1の端部の少なくとも一部に存在する検出領域の全反射面2によって全反射される。ここで、検出領域は、基板1の中央部における光線10の透過率よりも小さい光線10の透過率を有する領域のことである。図1の基板1においては、全反射面2が形成されている、図1における左右方向(基板2の外周端部)の全領域を検出領域ということにする。具体的には、全反射面2のみならず、たとえば図1において光電センサ30が対向する基板1の裏面側の外周端部も検出領域に含めることとする。 In contrast, the light beam 10 incident on the edge of the substrate 1 (left and right sides of the substrate 1 in FIG. 1) has the same wavelength and the same intensity as the light beam 10 incident on the central portion of the substrate 1. As shown in FIG. 1, the light beam 10 incident on the central portion of 1 is not transmitted through the substrate 1, but is totally reflected by the total reflection surface 2 of the detection region existing at least at a part of the end portion of the substrate 1. Here, the detection region is a region having a transmittance of the light beam 10 that is smaller than the transmittance of the light beam 10 in the central portion of the substrate 1. In the substrate 1 of FIG. 1, the entire region in the left-right direction (outer peripheral edge of the substrate 2) in FIG. 1 where the total reflection surface 2 is formed is referred to as a detection region. Specifically, not only the total reflection surface 2 but also the outer peripheral end portion on the back surface side of the substrate 1 facing the photoelectric sensor 30 in FIG.
 図1の基板1において検出領域は、基板1の主表面に対して所定角度を有する全反射面2を備えることにより形成されている。すなわち、当該全反射面2は、検出領域における光線10を全反射することにより、検出領域に照射された光線10が基板1を透過する割合(透過率)を、検出領域以外の領域における光線10が基板1を透過する割合よりも小さくするという機能を発揮する。したがって、たとえば図1に示すように基板1の主表面に対して交差する(垂直な)方向から基板1に対して光線10を入射する場合に、全反射面2に入射した光線10が全反射面2にて全反射を起こすことができる角度となるように、全反射面2は基板1の主表面(図1の左右方向)に対して所定の角度αを有する傾斜面となっている。また、全反射面2の表面は、当該全反射面2に入射した光線10が乱反射を起こすことなく全反射することが可能な程度に面粗度を小さくすることが好ましい。このようにすれば、全反射面2に入射した光線10は、図1に示すように全反射される。 1, the detection region is formed by providing a total reflection surface 2 having a predetermined angle with respect to the main surface of the substrate 1. That is, the total reflection surface 2 totally reflects the light beam 10 in the detection region, and thus the ratio (transmittance) of the light beam 10 irradiated to the detection region through the substrate 1 is set to the light beam 10 in the region other than the detection region. Exerts the function of making the ratio smaller than the ratio of transmitting through the substrate 1. Therefore, for example, as shown in FIG. 1, when the light beam 10 is incident on the substrate 1 from a direction intersecting (perpendicular) to the main surface of the substrate 1, the light beam 10 incident on the total reflection surface 2 is totally reflected. The total reflection surface 2 is an inclined surface having a predetermined angle α with respect to the main surface of the substrate 1 (left and right direction in FIG. 1) so that the angle can cause total reflection at the surface 2. Further, it is preferable that the surface of the total reflection surface 2 has such a small surface roughness that the light beam 10 incident on the total reflection surface 2 can be totally reflected without causing irregular reflection. In this way, the light beam 10 incident on the total reflection surface 2 is totally reflected as shown in FIG.
 全反射面2に入射する光線10は全反射面2にて反射されるため、図1に示すように、検出領域の全反射面2と平面的に重なる位置(すなわち全反射面2の真下)に配置された、入射される光線10を認識(検出)する光電センサ30には光線10がほとんど到達しない。このことから、光電センサ30は、光電センサ30の上部に配置される基板1の存在により光線10が遮断されたと認識することができる。この結果、光電センサ30の検出する光量の変化により、基板1の存在を検出することができる。このように全反射面2を備えることにより、光線10が透過する材質で基板1が構成される場合であっても、光電センサ30は基板1の存在を認識(検出)することができる。 Since the light ray 10 incident on the total reflection surface 2 is reflected by the total reflection surface 2, as shown in FIG. 1, a position that overlaps the total reflection surface 2 in the detection area in a plane (that is, directly below the total reflection surface 2). The light beam 10 hardly reaches the photoelectric sensor 30 that is arranged at (1) and recognizes (detects) the incident light beam 10. From this, the photoelectric sensor 30 can recognize that the light beam 10 is blocked by the presence of the substrate 1 disposed on the photoelectric sensor 30. As a result, the presence of the substrate 1 can be detected by a change in the amount of light detected by the photoelectric sensor 30. By providing the total reflection surface 2 in this manner, the photoelectric sensor 30 can recognize (detect) the presence of the substrate 1 even when the substrate 1 is made of a material that transmits the light beam 10.
 図2は、図1の基板1における左側の全反射面2を拡大した断面図である。したがって図1の基板1における右側の領域については、図2において省略しているため、そのことを表わすために図2の右側に波線を施している。 FIG. 2 is an enlarged cross-sectional view of the left total reflection surface 2 in the substrate 1 of FIG. Accordingly, since the region on the right side of the substrate 1 in FIG. 1 is omitted in FIG. 2, a wavy line is provided on the right side in FIG.
 図2に示す基板1の全反射面2は、図1に示すように基板1の主表面(図1の左右方向に延在する面)と角度αをなしている。この角度αは、上述したようにたとえば基板1の主表面に垂直な方向から基板1に入射する光線10を全反射面2にて全反射させることができる角度である。 The total reflection surface 2 of the substrate 1 shown in FIG. 2 forms an angle α with the main surface of the substrate 1 (surface extending in the left-right direction in FIG. 1) as shown in FIG. The angle α is an angle at which the light beam 10 incident on the substrate 1 from a direction perpendicular to the main surface of the substrate 1 can be totally reflected by the total reflection surface 2 as described above.
 なお、全反射面2が配置されている検出領域は、図2に示すように基板1の外周端(図2における左端)からの主表面方向の距離(図2における左端から右側への距離)が0.1mm以上5mm以下の領域に形成されることが好ましい。すなわち、図2におけるA点からB点までを全反射面2とすれば、基板1の外周端からA点までの、主表面方向の距離L1は0.1mm以上、また基板1の外周端からB点までの、主表面方向の距離L2は5mm以下であることが好ましい。基板1の端面から0.1mm未満の領域を含め、図2における下側の主表面に交差するように全反射面2を配置すると、全反射面2と、図2における下側の主表面とのなす角度が小さくなる(鋭角となる)場合がある。この場合、当該外周端(鋭利な角度をなす基板1の端部)を起点として基板1がチッピングやへき開を起こす可能性がある。これを抑制するため、図2に示すように、外周端からの主表面方向の距離L1が0.1mm未満の領域についてはたとえば全反射面2よりも主表面に対する角度が大きな角度となるように端面を設けることが好ましい。また、外周端からA点までの端面の形状としては、図2に示すような平面であってもよいが当該端面の表面形状を曲面状としてもよい。なお、角度αの値によっては、上述した図2に示した外周端からA点までの端面を設けない構成(B点より外周側がすべて全反射面2となっている構成)としてもよい。 In addition, the detection area | region where the total reflection surface 2 is arrange | positioned is the distance (distance from the left end in FIG. 2 to the right side) of the main surface direction from the outer periphery end (left end in FIG. 2) of the board | substrate 1 as shown in FIG. Is preferably formed in a region of 0.1 mm to 5 mm. That is, if the total reflection surface 2 is from point A to point B in FIG. 2, the distance L1 in the main surface direction from the outer peripheral edge of the substrate 1 to the point A is 0.1 mm or more, and from the outer peripheral edge of the substrate 1 The distance L2 in the main surface direction to the point B is preferably 5 mm or less. When the total reflection surface 2 is arranged so as to intersect the lower main surface in FIG. 2 including a region less than 0.1 mm from the end surface of the substrate 1, the total reflection surface 2 and the lower main surface in FIG. May be small (a sharp angle). In this case, there is a possibility that the substrate 1 will be chipped or cleaved starting from the outer peripheral end (the end portion of the substrate 1 having a sharp angle). In order to suppress this, as shown in FIG. 2, for the region where the distance L1 in the main surface direction from the outer peripheral end is less than 0.1 mm, for example, the angle with respect to the main surface is larger than the total reflection surface 2. It is preferable to provide an end face. Further, the shape of the end surface from the outer peripheral end to the point A may be a plane as shown in FIG. 2, but the surface shape of the end surface may be a curved surface. Depending on the value of the angle α, a configuration in which the end surface from the outer peripheral end to the point A shown in FIG. 2 described above is not provided (a configuration in which the outer peripheral side from the point B is the total reflection surface 2) is possible.
 また、基板1の外周端から5mm以上の領域は基板1の主表面の中心部分に相当し、半導体素子などを形成する領域である。したがって、基板1の端面から5mm以上の領域に全反射面2を設けると、基板1の主表面上において半導体素子などを形成する領域が小さくなるため、半導体素子の生産性が低下することになる。このため、距離L2を5mm以下となるよう設定することが好ましい。 Further, the region of 5 mm or more from the outer peripheral edge of the substrate 1 corresponds to the central portion of the main surface of the substrate 1 and is a region where a semiconductor element or the like is formed. Therefore, if the total reflection surface 2 is provided in a region of 5 mm or more from the end surface of the substrate 1, the region for forming a semiconductor element or the like on the main surface of the substrate 1 is reduced, so that the productivity of the semiconductor device is lowered. . For this reason, it is preferable to set the distance L2 to be 5 mm or less.
 ここで、全反射面2は、基板1の主表面の端部の少なくとも一部に形成されていればよい。すなわち、基板1の主表面の端面からの距離がたとえば0.1mm以上5mm以下の領域の全体に、基板1の主表面の外周部を1周するように全反射面2を形成してもよいし、当該外周部の周方向における一部のみに全反射面2を形成してもよい。 Here, the total reflection surface 2 only needs to be formed on at least a part of the end portion of the main surface of the substrate 1. That is, the total reflection surface 2 may be formed so as to make one round of the outer peripheral portion of the main surface of the substrate 1 in the entire region whose distance from the end surface of the main surface of the substrate 1 is, for example, 0.1 mm or more and 5 mm or less. And you may form the total reflection surface 2 only in a part in the circumferential direction of the said outer peripheral part.
 続いて、本発明の実施の形態1に係る基板の製造方法について説明する。図3に示すように、本発明の実施の形態1に係る上述した基板1を形成する際には、まず基板を準備する工程(S10)を実施する。これは具体的には、半導体装置の製造装置(たとえば成膜装置やエッチング装置など)といった装置において基板の検出のために照射される光線10(図1参照)を用いて、当該装置において存在を認識することができる透明な基板1(図1参照)を形成する元となる透明基板を準備する工程である。 Subsequently, a method for manufacturing a substrate according to Embodiment 1 of the present invention will be described. As shown in FIG. 3, when forming the above-described substrate 1 according to the first embodiment of the present invention, first, a step of preparing the substrate (S10) is performed. Specifically, this is achieved by using a light beam 10 (see FIG. 1) irradiated for detecting a substrate in an apparatus such as a semiconductor device manufacturing apparatus (for example, a film forming apparatus or an etching apparatus). This is a step of preparing a transparent substrate to be a base for forming a transparent substrate 1 (see FIG. 1) that can be recognized.
 ここで準備する基板は、当該基板の一方の主表面上に半導体素子などを形成してパワーデバイスなどの半導体装置を形成するための半導体基板であり、たとえば可視光(赤色光)や赤外光などの光線10を10%以上透過する透明な半導体基板が好ましい。具体的には、たとえばSiC、GaN、サファイア、AlN、ダイアモンドからなる群から選択された少なくとも1種を含む材質からなる基板である。 The substrate prepared here is a semiconductor substrate for forming a semiconductor device such as a power device by forming a semiconductor element on one main surface of the substrate, for example, visible light (red light) or infrared light. A transparent semiconductor substrate that transmits 10% or more of the light beam 10 is preferable. Specifically, the substrate is made of a material including at least one selected from the group consisting of SiC, GaN, sapphire, AlN, and diamond, for example.
 なお、この基板を準備する工程(S10)では、所定厚み、所定の主表面の大きさを有する上述した基板を外部から購入するなどして準備してもよいが、たとえばチョクラルスキー法やボート法、溶液成長法などを用いて当該半導体基板を構成する結晶からなるインゴットを形成し、当該インゴットをたとえばワイヤソーを用いて所定の厚み、所定の主表面の大きさを有する基板としての形状に切断することにより、基板を準備してもよい。 In the step of preparing the substrate (S10), the above-described substrate having a predetermined thickness and a predetermined main surface size may be purchased from the outside. For example, the Czochralski method or boat Forming an ingot made of a crystal constituting the semiconductor substrate using a method, a solution growth method, etc., and cutting the ingot into a shape as a substrate having a predetermined thickness and a predetermined main surface size using, for example, a wire saw By doing so, a substrate may be prepared.
 上述したように半導体装置の基板として用いる透明な基板が準備できたところで、加工工程(S20)を行なう。これは具体的には、基板を準備する工程(S10)にて準備した基板の端部の少なくとも一部の領域における光の透過率を検出領域として機能させるために、基板の主表面の中央部における光の透過率よりも当該領域の透過率を小さくするための加工を行なう工程である。ここで光の透過率を小さくするとは具体的に、上述したように基板のうち当該領域における光の透過率が、基板のうち当該領域以外の(すなわち透過率を小さくする加工を施していない領域の)光の透過率より小さくなるように加工を行なうことを意味する。また、好ましくは、当該領域における光の透過率が、当該領域以外の光の透過率の10%以下となるように加工を行なうことを意味する。このようにすれば、製造装置にて当該基板を処理する際に、基板が透明であっても、光の透過が遮断されたことをたとえば光電センサ30(図1参照)にて認識することが可能となる。したがって、基板の存在を検出することが可能となる。 As described above, when a transparent substrate used as a substrate for a semiconductor device is prepared, a processing step (S20) is performed. Specifically, in order to make the light transmittance in at least a partial region of the end portion of the substrate prepared in the step (S10) of preparing the substrate function as a detection region, the central portion of the main surface of the substrate This is a step of performing processing for making the transmittance of the region smaller than the transmittance of the light in. Here, specifically, to reduce the light transmittance, as described above, the light transmittance in the region of the substrate is a region other than the region of the substrate (that is, the region not subjected to processing for reducing the transmittance). This means that the processing is performed so as to be smaller than the light transmittance. Preferably, the processing means that the light transmittance in the region is 10% or less of the light transmittance in other regions. In this way, when the substrate is processed in the manufacturing apparatus, even if the substrate is transparent, it is recognized by, for example, the photoelectric sensor 30 (see FIG. 1) that light transmission is blocked. It becomes possible. Therefore, the presence of the substrate can be detected.
 この加工工程(S20)では、基板の主表面の端部の少なくとも一部の領域における光の透過率を、基板の主表面の中央部における光の透過率よりも小さくするために、基板の端部の少なくとも一部に入射する光を全反射する全反射面を形成する工程を行なう。この結果、図1に示す、基板1の主表面(図1の左右方向)に交差する方向、たとえば垂直な方向に進む光線10を照射した場合に全反射を起こすことができる条件を満たす所定の角度αを有する全反射面2が形成される。図1に示すように、基板1の表面のうち全反射面2以外の領域に照射された光線10は、基板1が透明なためほとんどが基板1を透過するが、検出領域の全反射面2に照射した光線10は全反射するため、図1に示すように基板1に関して全反射面2と平面的に重なる位置(すなわち全反射面2の真下)に配置された光電センサ30にはほとんど光線10が到達しない。このため、光電センサ30は基板1の存在により光線10が遮断されたと認識することができるので、基板1の存在を検出することができる。 In this processing step (S20), in order to make the light transmittance in at least a part of the end portion of the main surface of the substrate smaller than the light transmittance in the central portion of the main surface of the substrate, A step of forming a total reflection surface that totally reflects light incident on at least a part of the portion is performed. As a result, as shown in FIG. 1, predetermined conditions satisfying conditions that can cause total reflection when irradiated with a light beam 10 traveling in a direction intersecting the main surface of substrate 1 (left-right direction in FIG. 1), for example, a vertical direction. A total reflection surface 2 having an angle α is formed. As shown in FIG. 1, most of the light beam 10 applied to the region other than the total reflection surface 2 on the surface of the substrate 1 is transmitted through the substrate 1 because the substrate 1 is transparent, but the total reflection surface 2 in the detection region. As shown in FIG. 1, almost all of the light beam 10 is applied to the photoelectric sensor 30 disposed at a position overlapping the total reflection surface 2 in a plane with respect to the substrate 1 (that is, directly below the total reflection surface 2). 10 does not reach. For this reason, since the photoelectric sensor 30 can recognize that the light beam 10 is blocked by the presence of the substrate 1, the presence of the substrate 1 can be detected.
 図4および図5を参照して、本発明の基板の形態の変形例を説明する。
 全反射面2は、図1に示すように、基板1の外周部の端面のほぼ全体が全反射面2となるように形成されていてもよいが、たとえば図4に示す基板3のように、検出領域に全反射面2と、従来から用いられる通常のベベルカット面4とが共存した構造となっていてもよい。すなわち光線10が入射する側(図4における上側)に全反射面2を、基板3の主表面(図4における左右方向)とのなす角度が光線10を全反射する条件を満たす角度となるように形成し、光線10が入射する側と反対側(図4における下側)には通常の、たとえば基板3のチッピングやへき開を抑制するためのベベルカット面4を形成した構造であってもよい。なお、ベベルカット面4は、図4に示すように全反射面4との接続部の角部の角度が鋭角となるように、基板3の全反射面2が形成された側の主表面と反対側の主表面(裏面)に向かうにつれて基板3の幅が小さくなるように、全反射面2とは逆方向に傾斜するよう形成されている。
With reference to FIG. 4 and FIG. 5, the modification of the form of the board | substrate of this invention is demonstrated.
As shown in FIG. 1, the total reflection surface 2 may be formed so that almost the entire end face of the outer peripheral portion of the substrate 1 becomes the total reflection surface 2. For example, like the substrate 3 shown in FIG. The total reflection surface 2 and the conventional bevel cut surface 4 used conventionally may coexist in the detection region. That is, the angle formed by the total reflection surface 2 on the side on which the light beam 10 is incident (upper side in FIG. 4) and the main surface of the substrate 3 (left-right direction in FIG. 4) is an angle that satisfies the condition for total reflection of the light beam 10. A normal structure, for example, a bevel cut surface 4 for suppressing chipping or cleavage of the substrate 3 may be formed on the side opposite to the side on which the light beam 10 is incident (the lower side in FIG. 4). . The bevel cut surface 4 has a main surface on the side where the total reflection surface 2 of the substrate 3 is formed so that the angle of the corner of the connection portion with the total reflection surface 4 is an acute angle as shown in FIG. The substrate 3 is formed so as to be inclined in the opposite direction to the total reflection surface 2 so that the width of the substrate 3 becomes smaller toward the opposite main surface (back surface).
 またはたとえば図5に示す基板5のように、全反射面2を、上述した基板5の全反射面2と同様の条件を満足する角度となるように形成し、光線10が入射する側と反対側(図5における下側)には基板5の主表面(図5における左右方向)とほぼ垂直をなす端面6および通常のベベルカット面7を形成した構造であってもよい。つまり、ことなる観点から言えば、基板5の外周端は、全反射面2とベベルカット面7とが、主表面に対してほぼ垂直な端面6をはさんで配置された構成となっていてもよい。 Or, for example, like the substrate 5 shown in FIG. 5, the total reflection surface 2 is formed to have an angle satisfying the same conditions as the total reflection surface 2 of the substrate 5 described above, and opposite to the side on which the light beam 10 is incident. On the side (lower side in FIG. 5), an end surface 6 and a normal bevel cut surface 7 that are substantially perpendicular to the main surface (left-right direction in FIG. 5) of the substrate 5 may be formed. That is, from a different point of view, the outer peripheral edge of the substrate 5 has a configuration in which the total reflection surface 2 and the bevel cut surface 7 are arranged with the end surface 6 being substantially perpendicular to the main surface. Also good.
 その他、図示しないが、図4および図5における各基板の検出領域において、全反射面2の下側(光線10が入射される側の反対側)には、ベベルカット面4、7や端面6の代わりに、たとえば全反射面2に連なるように、図15の基板の端部(図15における左側)に形成されたラウンド(表面が曲面状の部分)を形成してもよい。このように各基板の全反射面2の下側には、たとえば応力による基板のへき開やチッピングなどを抑制するための任意の形状を設けることができる。 In addition, although not shown, in the detection region of each substrate in FIGS. 4 and 5, the bevel cut surfaces 4 and 7 and the end surface 6 are provided below the total reflection surface 2 (opposite the side on which the light beam 10 is incident). Instead of this, for example, a round (surface having a curved surface) formed at the end of the substrate in FIG. 15 (left side in FIG. 15) may be formed so as to be continuous with the total reflection surface 2. As described above, an arbitrary shape for suppressing cleavage and chipping of the substrate due to stress, for example, can be provided under the total reflection surface 2 of each substrate.
 以上に述べた、本発明の実施の形態1に係る各基板の全反射面2を形成する工程には、たとえば端部の少なくとも一部を機械加工する工程を含んでいてもよいし、端部の少なくとも一部をレーザ加工する工程を含んでいてもよい。たとえば研削用の砥石を用いて、基板1の主表面の端部の所定の領域を、主表面にほぼ垂直な方向から照射される光線10を全反射する条件を満たす角度となるように除去加工することにより全反射面2を形成することができる。またはレーザを用いて、同様に基板1の端部を除去加工することにより全反射面2を形成してもよい。 The step of forming total reflection surface 2 of each substrate according to the first embodiment of the present invention described above may include, for example, a step of machining at least a part of the end portion. May include a step of laser processing at least a part thereof. For example, using a grinding wheel, a predetermined region at the end of the main surface of the substrate 1 is removed so as to satisfy an angle that satisfies the condition for total reflection of the light beam 10 irradiated from a direction substantially perpendicular to the main surface. By doing so, the total reflection surface 2 can be formed. Alternatively, the total reflection surface 2 may be formed by removing the end portion of the substrate 1 in the same manner using a laser.
 ここで、照射される光線10を全反射することができる程度に、形成する全反射面2の面粗度が小さくなるよう加工することが好ましい。具体的には当該面粗度はRaで0.5nm以下となるように加工することが好ましく、そのなかでもRaで0.1nm以下であることがさらに好ましい。上述した面粗度とすることにより、照射される光線10を容易に全反射することができる。そのように加工するためには、たとえば機械加工により全反射面2を形成する場合、仕上げ加工において用いる砥石の粒度が100nm以下であることが好ましい。また、レーザを用いて全反射面2を形成する場合においては、波長266nmのUVレーザを照射することが好ましい。 Here, it is preferable that the surface roughness of the total reflection surface 2 to be formed is reduced to such an extent that the irradiated light beam 10 can be totally reflected. Specifically, the surface roughness is preferably processed so that Ra is 0.5 nm or less, and more preferably Ra is 0.1 nm or less. By setting the surface roughness as described above, the irradiated light beam 10 can be easily totally reflected. In order to perform such processing, for example, when the total reflection surface 2 is formed by machining, it is preferable that the particle size of the grindstone used in the finishing process is 100 nm or less. Moreover, when forming the total reflection surface 2 using a laser, it is preferable to irradiate UV laser with a wavelength of 266 nm.
 (実施の形態2)
 図6に示す本発明の実施の形態2に係る基板8は、図1に示す本発明の実施の形態1に係る基板1と基本的に同様の態様を備えている。しかし、図6に示す基板8は、図1などに示す全反射面2に代えて、検出領域において入射する光線10を乱反射させる乱反射面9を備えている。この点において、基板8と基板1とは相違している。
(Embodiment 2)
A substrate 8 according to the second embodiment of the present invention shown in FIG. 6 has basically the same mode as the substrate 1 according to the first embodiment of the present invention shown in FIG. However, the substrate 8 shown in FIG. 6 includes an irregular reflection surface 9 for irregularly reflecting the incident light beam 10 in the detection region, instead of the total reflection surface 2 shown in FIG. In this respect, the substrate 8 and the substrate 1 are different.
 基板8の一方の主表面に対向する領域(図6における上側)から照射される光線10が基板8の一方の主表面と反対側に位置する他方の主表面(図6における下側)へ透過することを抑制できれば、基板8の下側に位置する光電センサ30は光線10が基板8により遮断されたことを認識することができるので、基板8の存在を検出することができる。したがって基板8における光線10の透過を抑制するためには、図1に示す基板1のように入射した光線10を全反射させてもよいが、図6に示す基板8のように乱反射面9により光線10を乱反射させることによっても、全反射させる場合と同様の効果を奏することができる。 A light beam 10 irradiated from a region (upper side in FIG. 6) facing one main surface of the substrate 8 is transmitted to the other main surface (lower side in FIG. 6) located on the opposite side of the one main surface of the substrate 8. If this can be suppressed, the photoelectric sensor 30 positioned below the substrate 8 can recognize that the light beam 10 has been blocked by the substrate 8, and therefore the presence of the substrate 8 can be detected. Therefore, in order to suppress the transmission of the light beam 10 through the substrate 8, the incident light beam 10 may be totally reflected as in the substrate 1 shown in FIG. 1, but the diffuse reflection surface 9 as in the substrate 8 shown in FIG. The effect similar to the case where the light beam 10 is diffusely reflected can be obtained.
 図7は、図6の基板8における左側の乱反射面9を拡大した断面図である。したがって図6の基板8における右側の領域について、図7においては記載していない。そのため、図7の右側に波線を記載し、基板8が右側へと延在していることを示唆している。 FIG. 7 is an enlarged cross-sectional view of the left irregular reflection surface 9 in the substrate 8 of FIG. Therefore, the region on the right side of the substrate 8 in FIG. 6 is not shown in FIG. Therefore, a wavy line is shown on the right side of FIG. 7, suggesting that the substrate 8 extends to the right side.
 図7に示す乱反射面9は、図2に示す全反射面2に対して面粗度を上げる加工を施した構成となっている。すなわち図2と同様に、図7に示すように基板8の乱反射面9は、基板8の主表面(図7の左右方向に延在する面)と角度αをなしている。なお、ここで面粗度を上げるとは、当該面に入射する光線10を乱反射させることができる面粗度となるように表面を荒らすように(凹凸形状を形成するように)加工することをいうが、より具体的には当該面の面粗度がRaで0.1μm以上となるように加工することをいう。 The irregular reflection surface 9 shown in FIG. 7 has a configuration in which processing for increasing the surface roughness is performed on the total reflection surface 2 shown in FIG. That is, similarly to FIG. 2, as shown in FIG. 7, the irregular reflection surface 9 of the substrate 8 forms an angle α with the main surface of the substrate 8 (surface extending in the left-right direction in FIG. 7). Here, to increase the surface roughness means to process the surface so as to have a surface roughness that can diffusely reflect the light beam 10 incident on the surface (to form an uneven shape). More specifically, it means that the surface is processed so that the surface roughness Ra is 0.1 μm or more.
 乱反射面9としての機能を発揮するために表面の面粗度を上げる加工が施されている領域である検出領域は、図7に示すように基板8の外周端(図7における左端)からの主表面方向の(図7における左端から右側への)距離が0.1mm以上5mm以下の領域に形成されることが好ましい。すなわち、図7におけるC点からD点までを乱反射面9とすれば、基板8の外周端からC点までの、主表面方向の距離L3は0.1mm以上、基板8の外周端からD点までの、主表面方向の距離L4は5mm以下であることが好ましい。 As shown in FIG. 7, the detection region, which is a region subjected to processing for increasing the surface roughness in order to exhibit the function as the irregular reflection surface 9, is from the outer peripheral end (left end in FIG. 7) of the substrate 8. It is preferable that the distance in the main surface direction (from the left end to the right side in FIG. 7) is 0.1 mm to 5 mm. That is, if the irregular reflection surface 9 is from point C to point D in FIG. 7, the distance L3 in the main surface direction from the outer peripheral edge of the substrate 8 to the point C is 0.1 mm or more, and the point D from the outer peripheral edge of the substrate 8. The distance L4 in the main surface direction is preferably 5 mm or less.
 乱反射面9についても、基板8の主表面の端部の少なくとも一部に形成されていればよい。すなわち、基板8の主表面の端面からの距離がたとえば0.1mm以上5mm以下の領域の全体に、基板8の主表面の外周部を1周するように乱反射面9を形成してもよいし、当該外周部における周方向の一部のみに乱反射面9を形成してもよい。 The irregular reflection surface 9 may be formed on at least a part of the end portion of the main surface of the substrate 8. That is, the irregular reflection surface 9 may be formed so as to make one round of the outer peripheral portion of the main surface of the substrate 8 in the entire region whose distance from the end surface of the main surface of the substrate 8 is, for example, 0.1 mm or more and 5 mm or less. Alternatively, the irregular reflection surface 9 may be formed only on a part of the outer peripheral portion in the circumferential direction.
 なお、図7に示すような、全反射面2の面粗度を上げることにより乱反射面9を形成する例は一例である。他にはたとえば図示しないが、全反射面を一旦形成することなく(つまり基板8の端部については傾斜部など形成せず)、基板8の主表面の端部に面粗度の大きい乱反射面9を形成した構造としてもよい。また、乱反射面9を形成するために基板8の一方の主表面(図6、7の上側の主表面)および他方の主表面(図6、7の下側の主表面)と交差する面を形成する場合においても、当該交差する面と基板8の主表面とのなす角が、たとえば図7に示す角度αのように、光線10が全反射を起こす条件を満たす角度である必要はない。 In addition, the example which forms the irregular reflection surface 9 by raising the surface roughness of the total reflection surface 2 as shown in FIG. 7 is an example. Other than that, for example, although not shown, a diffuse reflection surface having a large surface roughness at the end of the main surface of the substrate 8 without once forming a total reflection surface (that is, without forming an inclined portion or the like at the end of the substrate 8). 9 may be formed. Further, in order to form the irregular reflection surface 9, a surface intersecting with one main surface (the upper main surface in FIGS. 6 and 7) and the other main surface (the lower main surface in FIGS. 6 and 7) of the substrate 8 is formed. Even in the case of formation, the angle formed between the intersecting surface and the main surface of the substrate 8 does not need to be an angle that satisfies the condition for causing the light ray 10 to undergo total reflection, such as an angle α shown in FIG.
 本発明の実施の形態2に係る基板においても、たとえば上述した図4に示す基板3と同様に、図8に示す基板11のように、乱反射面9と、従来から用いられる通常のベベルカット面4とが共存した構造となっていてもよい。またはたとえば図9に示す基板12のように、上述した図5における基板5と同様に、乱反射面9と、端面6およびベベルカット面7とが共存した構造であってもよい。その他、各基板の乱反射面9の下側には、たとえば応力による基板のへき開やチッピングなどを抑制するための任意の形状を設けることができる。 Also in the substrate according to the second embodiment of the present invention, like the substrate 3 shown in FIG. 4 as described above, for example, as in the substrate 11 shown in FIG. 4 may coexist. Or, for example, like the substrate 12 shown in FIG. 9, similarly to the substrate 5 in FIG. 5 described above, a structure in which the irregular reflection surface 9, the end surface 6, and the bevel cut surface 7 coexist may be used. In addition, an arbitrary shape for suppressing cleavage and chipping of the substrate due to stress, for example, can be provided below the irregular reflection surface 9 of each substrate.
 続いて、本発明の実施の形態2に係る基板の製造方法について説明する。本発明の実施の形態2に係る基板8の製造方法についても、上述した図3に示すように、まず基板を準備する工程(S10)において、半導体装置の基板として用いる透明な基板を準備する。次に加工工程(S20)において、基板の端部の少なくとも一部の領域における光の透過率を、基板の主表面の中央部における光の透過率よりも小さくするための加工を行なう。ここで本発明の実施の形態2においては、たとえば図6に示す基板8のように、加工工程(S20)には、基板8の主表面の端部の少なくとも一部に入射する光を乱反射する乱反射面9を形成する工程を含む。 Then, the manufacturing method of the board | substrate which concerns on Embodiment 2 of this invention is demonstrated. Also for the method for manufacturing the substrate 8 according to the second embodiment of the present invention, as shown in FIG. 3 described above, first, in the step of preparing the substrate (S10), a transparent substrate to be used as the substrate of the semiconductor device is prepared. Next, in the processing step (S20), processing is performed to make the light transmittance in at least a partial region of the end portion of the substrate smaller than the light transmittance in the central portion of the main surface of the substrate. Here, in the second embodiment of the present invention, for example, as in the substrate 8 shown in FIG. 6, in the processing step (S20), light incident on at least a part of the end portion of the main surface of the substrate 8 is irregularly reflected. A step of forming the irregular reflection surface 9 is included.
 図6に示すように、基板8の乱反射面9以外の領域に照射された光線10は、基板8が透明なためほとんどが基板8を透過する。しかし、検出領域に配置された乱反射面9に照射した光線10は当該乱反射面9において乱反射するため、図6における基板8の下側に配置された光電センサ30にはほとんど光線10が到達しない。このため、光電センサ30は基板8の存在により光線10が遮断されたと認識することができるので、基板8の存在を検出することができる。 As shown in FIG. 6, most of the light beam 10 irradiated on the region other than the irregular reflection surface 9 of the substrate 8 is transmitted through the substrate 8 because the substrate 8 is transparent. However, since the light beam 10 applied to the irregular reflection surface 9 arranged in the detection region is irregularly reflected on the irregular reflection surface 9, the light beam 10 hardly reaches the photoelectric sensor 30 arranged on the lower side of the substrate 8 in FIG. For this reason, since the photoelectric sensor 30 can recognize that the light beam 10 is blocked by the presence of the substrate 8, the presence of the substrate 8 can be detected.
 このとき、たとえば図7に示す基板8のように、まず乱反射面9を形成するために基板8の一方の主表面(図7の上側の主表面)および他方の主表面(図7の下側の主表面)と交差する面を形成し、形成した面の面粗度を上げる加工を施してもよい。ここで、当該交差する面が基板8の主表面となす角度はたとえば主表面に垂直な方向から入射する光線10が全反射する条件を満たす角度α(図1参照)であってもよいが、それ以外の任意の角度とすることができる。また、上述した交差する面を形成することなく、基板8の主表面の端部に面粗度の大きい乱反射面9を形成してもよい。いずれの場合においても、乱反射面9としての機能を発揮するための面粗度の大きい領域は、基板8の主表面の端面から0.1mm以上5mm以下の領域に形成することが好ましい。 At this time, as in the substrate 8 shown in FIG. 7, for example, first, the main surface (the upper main surface in FIG. 7) and the other main surface (the lower side in FIG. 7) of the substrate 8 are formed in order to form the irregular reflection surface 9. A surface intersecting with the main surface) may be formed, and processing for increasing the surface roughness of the formed surface may be performed. Here, the angle formed by the intersecting surface with the main surface of the substrate 8 may be, for example, an angle α (see FIG. 1) that satisfies the condition that the light ray 10 incident from a direction perpendicular to the main surface is totally reflected. Any other angle can be used. Alternatively, the irregular reflection surface 9 having a large surface roughness may be formed at the end of the main surface of the substrate 8 without forming the above-described intersecting surfaces. In any case, it is preferable that the region having a large surface roughness for exhibiting the function as the irregular reflection surface 9 is formed in a region from 0.1 mm to 5 mm from the end surface of the main surface of the substrate 8.
 以上に述べた、本発明の実施の形態2に係る基板の乱反射面9を形成する工程には、本発明の実施の形態1に係る基板の全反射面2を形成する工程と同様に、たとえば端部の少なくとも一部を機械加工する工程を含んでいてもよいし、端部の少なくとも一部をレーザ加工する工程を含んでいてもよい。たとえば上述した機械加工する工程を用いる場合は、砥石を用いて、基板8に示すような乱反射面9を形成するための形状(基板8の主表面に対して傾斜した端面形状)を加工し、かつ面粗度を大きくする加工を施すという方法を用いる。また、端面の少なくとも一部をレーザ加工する工程を用いる場合には、所定の領域にレーザを照射することにより面粗度を大きくする加工を行なう。具体的には、波長266nmのUVレーザを照射することが好ましい。 In the step of forming the irregular reflection surface 9 of the substrate according to the second embodiment of the present invention described above, as in the step of forming the total reflection surface 2 of the substrate according to the first embodiment of the present invention, for example, A step of machining at least a portion of the end portion may be included, and a step of laser machining at least a portion of the end portion may be included. For example, when using the machining step described above, a shape for forming the irregular reflection surface 9 as shown in the substrate 8 (end surface shape inclined with respect to the main surface of the substrate 8) is processed using a grindstone, And the method of giving the process which enlarges surface roughness is used. Further, in the case of using a step of laser processing at least a part of the end face, processing for increasing the surface roughness is performed by irradiating a predetermined region with laser. Specifically, it is preferable to irradiate a UV laser having a wavelength of 266 nm.
 その他、乱反射面9を形成する方法としては、たとえば以下に述べる方法を用いることもできる。図10に示すように、当該方法においてはまず不純物を導入する工程(S21)として、基板のうち乱反射面を形成する領域、すなわち基板の端部の少なくとも一部の領域に対して不純物の導入を行なう工程を実施する。 In addition, as a method of forming the irregular reflection surface 9, for example, a method described below can be used. As shown in FIG. 10, in the method, as the step of introducing impurities (S21), the introduction of impurities into the region of the substrate where the irregular reflection surface is formed, that is, at least a portion of the edge of the substrate is introduced. The process to perform is implemented.
 図11に示すように、基板8のうち乱反射面を形成したい領域、すなわち基板8の主表面の端部(たとえば図11の基板8における左端)から0.1mm以上5mm以下の領域に対し、主表面から基板8の内部にイオン注入を行なうことにより、基板8を構成する結晶の欠陥13を形成する。ここでイオン注入する物質としては、たとえばB(ボロン)、N(窒素)、Al(アルミニウム)、P(リン)などを用いることが好ましい。ここで、イオン注入を行なう場合に、導入される不純物の密度(濃度)は、1.0E17cm-3以上1.0E21cm-3以下であることが好ましく、そのなかでも1.0E19cm-3以上1.0E20cm-3以下であることがより好ましい。上記範囲の密度(濃度)とすれば、当該領域に入射する光線10を乱反射する作用を大きくすることができる。 As shown in FIG. 11, the region of the substrate 8 where the irregular reflection surface is to be formed, that is, the region of 0.1 mm or more and 5 mm or less from the end of the main surface of the substrate 8 (for example, the left end in the substrate 8 of FIG. 11) Ions are implanted from the surface into the substrate 8 to form crystal defects 13 constituting the substrate 8. Here, it is preferable to use, for example, B (boron), N (nitrogen), Al (aluminum), P (phosphorus) or the like as a substance to be ion-implanted. Here, when ion implantation is performed, the density (concentration) of impurities to be introduced is preferably 1.0E17 cm −3 or more and 1.0E21 cm −3 or less, and 1.0E19 cm −3 or more and 1. More preferably, it is 0E20 cm −3 or less. When the density (concentration) is in the above range, the effect of irregularly reflecting the light beam 10 incident on the region can be increased.
 続いて図10に示すようにエッチングする工程(S22)を行なう。具体的には、上述した不純物を導入する工程(S21)にてイオン注入を行なった基板の表面層にウェットエッチング処理を行なう工程である。 Subsequently, an etching step (S22) is performed as shown in FIG. Specifically, this is a step of performing a wet etching process on the surface layer of the substrate on which the ions have been implanted in the step of introducing impurities (S21).
 図12に示すように、たとえばイオン注入により欠陥13を形成した基板8を、KOH溶液14中に浸漬する。ここでKOHとは水酸化カリウムで、強アルカリ性であり強いエッチング性を有する物質である。すると基板8のうち欠陥13が形成された領域においては、欠陥13が存在することにより基板8の主表面のエッチング速度が局所的に変わる(均一ではない)ため、エッチングされた面に凹凸が形成される。その結果、当該欠陥が形成された領域における表面の面粗度が増加する。また、基板8のうち欠陥13が存在しない領域においては上記のような欠陥の影響が無いため、均一なエッチングが行なわれる。そのため、主表面がエッチングされる量は当該領域内においてほぼ同一であり、主表面の面粗度は大きく変化しない。 As shown in FIG. 12, for example, the substrate 8 on which the defect 13 is formed by ion implantation is immersed in the KOH solution 14. Here, KOH is potassium hydroxide, which is a strongly alkaline substance having a strong etching property. Then, in the region of the substrate 8 where the defect 13 is formed, the etching rate of the main surface of the substrate 8 is locally changed (not uniform) due to the presence of the defect 13, so that irregularities are formed on the etched surface. Is done. As a result, the surface roughness of the surface where the defect is formed increases. Further, in the region where the defect 13 does not exist in the substrate 8, there is no influence of the defect as described above, so that uniform etching is performed. Therefore, the amount by which the main surface is etched is substantially the same in the region, and the surface roughness of the main surface does not change greatly.
 以上の手順により、基板8の主表面のうち、イオン注入を行なって結晶の欠陥13が発生した領域のみ面粗度を大きくすることができる。このため、イオン注入を行なった領域の主表面を乱反射面として利用することができる。 By the above procedure, the surface roughness can be increased only in the region of the main surface of the substrate 8 where ion implantation is performed and crystal defects 13 are generated. For this reason, the main surface of the ion-implanted region can be used as the irregular reflection surface.
 また、不純物を導入する方法として、上述したイオン注入法の代わりに、たとえば熱拡散法を用いてもよい。図13に示すように、この場合においても図10に示したイオン注入法を用いる場合と同様に、まず不純物を導入する工程(S21)を実施する。この後、図13に示すように、図10に示すイオン注入法におけるエッチングする工程(S22)の代わりに、熱処理する工程(S23)を行なう。この結果、導入された不純物の存在に起因して、不純物を導入した領域に欠陥が形成され、結果的に不純物を導入した領域の表面に凹凸が形成される。 Further, as a method for introducing impurities, for example, a thermal diffusion method may be used instead of the above-described ion implantation method. As shown in FIG. 13, in this case as well, as in the case of using the ion implantation method shown in FIG. 10, an impurity introduction step (S21) is first performed. Thereafter, as shown in FIG. 13, a heat treatment step (S23) is performed instead of the etching step (S22) in the ion implantation method shown in FIG. As a result, due to the presence of the introduced impurity, a defect is formed in the region where the impurity is introduced, and as a result, irregularities are formed on the surface of the region where the impurity is introduced.
 なお、上述した不純物を導入する工程では、図10に示したイオン注入法を用いてもよいが、他の方法を用いてもよい。具体的には、たとえば不純物を含む物体を、基板の不純物を導入したい領域に接触した状態で、基板および当該物体を過熱する。その結果、当該物体から固体拡散により不純物が基板の内部へと拡散する。 In the step of introducing the impurity described above, the ion implantation method shown in FIG. 10 may be used, but other methods may be used. Specifically, for example, the substrate and the object are overheated in a state where the object including the impurity is in contact with a region of the substrate where the impurity is to be introduced. As a result, impurities diffuse from the object into the substrate by solid diffusion.
 あるいは、基板において不純物を導入したい領域のみが露出するようにマスク層を形成し、当該マスク層が形成された基板を熱処理炉において加熱する。この加熱時に、熱処理炉の雰囲気ガスとして、導入したい不純物を含有するガスを用いる。このようにすれば、熱処理により基板の所定の領域(マスク層が形成されていない領域)に不純物を導入することができる。 Alternatively, a mask layer is formed so that only a region where impurities are to be introduced is exposed in the substrate, and the substrate on which the mask layer is formed is heated in a heat treatment furnace. During this heating, a gas containing an impurity to be introduced is used as an atmosphere gas in the heat treatment furnace. In this way, impurities can be introduced into a predetermined region of the substrate (region where the mask layer is not formed) by heat treatment.
 以上の方法(熱拡散法)を用いて不純物を導入した後、上記熱処理する工程(S23)を行なえば、基板の主表面のうち不純物を導入した領域の凹凸を増加させることができるため、イオン注入法を用いた場合と同様に乱反射面を形成することができる。 When the impurity is introduced using the above method (thermal diffusion method) and then the heat treatment step (S23) is performed, the unevenness of the region into which the impurity is introduced in the main surface of the substrate can be increased. As in the case of using the injection method, the irregular reflection surface can be formed.
 本発明の実施の形態2は、以上に述べた各点についてのみ、本発明の実施の形態1と異なる。すなわち、本発明の実施の形態2について、上述しなかった構成や条件、手順や効果などは、全て本発明の実施の形態1に順ずる。 The second embodiment of the present invention is different from the first embodiment of the present invention only in each of the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the second embodiment of the present invention are all in accordance with the first embodiment of the present invention.
 (実施の形態3)
 図14に示す基板15は、検出領域として用いる、たとえば基板15の一方の主表面(図14における上側の主表面)のうち端面から0.1mm以上5mm以下の領域に薄膜16を備えている。この薄膜16は、基板15の上側から基板15の主表面に対して基板15の主表面にほぼ垂直な方向に入射する光線10を乱反射させるものである。ここで薄膜16の材質としては、たとえばCr(クロム)、W(タングステン)、Al(アルミニウム)など、可視光(赤色光)や赤外光などを高い割合で反射することができる金属薄膜を用いることが好ましい。
(Embodiment 3)
The substrate 15 shown in FIG. 14 includes a thin film 16 used as a detection region, for example, in one main surface (the upper main surface in FIG. 14) of the substrate 15 in a region from 0.1 mm to 5 mm from the end face. The thin film 16 diffusely reflects the light beam 10 incident on the main surface of the substrate 15 from the upper side of the substrate 15 in a direction substantially perpendicular to the main surface of the substrate 15. Here, as the material of the thin film 16, for example, a metal thin film that can reflect visible light (red light), infrared light, and the like at a high rate, such as Cr (chromium), W (tungsten), and Al (aluminum) is used. It is preferable.
 したがって、本発明の実施の形態3に係る基板15においても、たとえば上述した本発明の実施の形態2に係る基板8と同様に、検出領域に入射する光を薄膜16により乱反射することができる。このため基板15の下側(図14参照)に配置される光電センサ30に入射する光線10が減少する。このとき光電センサ30は光線10の遮断を認識することにより、基板15の存在を検出することができる。 Therefore, also in the substrate 15 according to the third embodiment of the present invention, the light incident on the detection region can be diffusely reflected by the thin film 16 as in the above-described substrate 8 according to the second embodiment of the present invention. For this reason, the light rays 10 incident on the photoelectric sensor 30 arranged on the lower side of the substrate 15 (see FIG. 14) are reduced. At this time, the photoelectric sensor 30 can detect the presence of the substrate 15 by recognizing the interruption of the light beam 10.
 本発明の実施の形態3に係る基板の製造方法は、上述した図3に示す本発明の実施の形態1に係る基板の製造方法の手順に順ずる。ただし、図3の加工工程(S20)において、基板の端部の少なくとも一部の領域における光の透過率を、基板の主表面の中央部における光の透過率よりも小さくする加工として、図14に示すように基板15の一方の主表面上に薄膜16を成膜する。この薄膜16は、乱反射面として使用するものであるため、たとえば上述した図6に示す基板8と同様に、基板15の主表面の端面からの主表面方向の距離が0.1mm以上5mm以下の領域に対して成膜を行なうことが好ましい。上述したように、薄膜16の材質としてはたとえばCr、W、Alなど、可視光(赤色光)や赤外光などを高い割合で反射することができる金属薄膜を用いることが好ましい。また、薄膜16の膜厚は0.05μm以上1.0μm以下とすることが好ましく、その中でも特に0.1μm以上0.5μm以下とすることがより好ましい。そして、このような薄膜16を成膜する方法としては、たとえば真空蒸着法やCVD法、スパッタリング法などを用いることが好ましい。 The substrate manufacturing method according to Embodiment 3 of the present invention follows the above-described procedure of the substrate manufacturing method according to Embodiment 1 of the present invention shown in FIG. However, in the processing step (S20) of FIG. 3, as the processing for making the light transmittance in at least a partial region of the end portion of the substrate smaller than the light transmittance in the central portion of the main surface of the substrate, FIG. As shown in FIG. 2, a thin film 16 is formed on one main surface of the substrate 15. Since this thin film 16 is used as an irregular reflection surface, the distance in the main surface direction from the end surface of the main surface of the substrate 15 is not less than 0.1 mm and not more than 5 mm, for example, similarly to the substrate 8 shown in FIG. It is preferable to form a film on the region. As described above, the material of the thin film 16 is preferably a metal thin film that can reflect visible light (red light), infrared light, and the like at a high rate, such as Cr, W, and Al. The film thickness of the thin film 16 is preferably 0.05 μm or more and 1.0 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less. And as a method of forming such a thin film 16, it is preferable to use a vacuum evaporation method, CVD method, sputtering method etc., for example.
 なお、本発明の実施の形態3においても、図示しないがたとえば図8に示す基板11のように、乱反射面として用いる薄膜16と、従来から用いられる通常のベベルカット面4とが共存した構造となっていてもよい。またはたとえば図9に示す基板12と同様に、乱反射面として用いる薄膜16と、端面6およびベベルカット面7とが共存した構造であってもよい。その他、各基板の乱反射面として用いる薄膜16の下側には、たとえば応力による基板のへき開やチッピングなどを抑制するための任意の形状を設けることができる。 Even in Embodiment 3 of the present invention, although not shown, for example, a substrate 11 as shown in FIG. 8 has a structure in which a thin film 16 used as a diffusely reflecting surface and a normal bevel cut surface 4 conventionally used coexist. It may be. Alternatively, for example, similarly to the substrate 12 shown in FIG. 9, a structure in which the thin film 16 used as the irregular reflection surface, the end surface 6 and the bevel cut surface 7 coexist may be used. In addition, an arbitrary shape can be provided on the lower side of the thin film 16 used as the irregular reflection surface of each substrate, for example, to suppress cleavage and chipping of the substrate due to stress.
 また、上述した薄膜16は乱反射面として形成されているが、薄膜16の表面状態などを制御して全反射面となるように薄膜16を形成してもよい。 Further, although the thin film 16 described above is formed as an irregular reflection surface, the thin film 16 may be formed to be a total reflection surface by controlling the surface state of the thin film 16 and the like.
 本発明の実施の形態3は、以上に述べた各点についてのみ、本発明の実施の形態2と異なる。すなわち、本発明の実施の形態3について、上述しなかった構成や条件、手順や効果などは、全て本発明の実施の形態2に順ずる。 The third embodiment of the present invention is different from the second embodiment of the present invention only in the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the third embodiment of the present invention are all in accordance with the second embodiment of the present invention.
 今回開示された各実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上述した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 Each embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
 本発明は、透明な基板を用いて半導体装置の製造などのプロセスを行なう場合に、当該透明な基板の存在をセンサに認識させることを可能とする技術として、特に優れている。 The present invention is particularly excellent as a technique that enables a sensor to recognize the presence of a transparent substrate when a process such as manufacturing a semiconductor device is performed using the transparent substrate.
 1,3,5,8,11,12,15,20 基板、2 全反射面、4,7 ベベルカット面、6 端面、9 乱反射面、10 光線、13 欠陥、14 KOH溶液、16 薄膜、30 光電センサ。 1, 3, 5, 8, 11, 12, 15, 20 substrate, 2, total reflection surface, 4, 7 bevel cut surface, 6 end surface, 9 irregular reflection surface, 10 light beam, 13 defect, 14 KOH solution, 16 thin film, 30 Photoelectric sensor.

Claims (14)

  1.  透明な基板(1、3、5、8、11、12、15、20)であり、
     前記基板(1、3、5、8、11、12、15、20)の端部の少なくとも一部に形成され、前記基板(1、3、5、8、11、12、15、20)の中央部における光の透過率よりも小さい前記光の透過率を有する検出領域(2、9、13)を備える基板。
    A transparent substrate (1, 3, 5, 8, 11, 12, 15, 20),
    Formed on at least a part of the end of the substrate (1, 3, 5, 8, 11, 12, 15, 20), the substrate (1, 3, 5, 8, 11, 12, 15, 20) A board | substrate provided with the detection area | region (2, 9, 13) which has the light transmittance smaller than the light transmittance in a center part.
  2.  前記検出領域(2、9、13)は、前記検出領域(2、9、13)に入射する前記光を全反射する全反射面(2)を含む、請求の範囲第1項に記載の基板。 The substrate according to claim 1, wherein the detection region (2, 9, 13) includes a total reflection surface (2) that totally reflects the light incident on the detection region (2, 9, 13). .
  3.  前記検出領域(2、9、13)は、前記検出領域(2、9、13)に入射する前記光を乱反射する乱反射面(9)を含む、請求の範囲第1項に記載の基板。 The substrate according to claim 1, wherein the detection area (2, 9, 13) includes an irregular reflection surface (9) for irregularly reflecting the light incident on the detection area (2, 9, 13).
  4.  前記基板(1、3、5、8、11、12、15、20)はSiC、GaN、サファイア、AlN、ダイアモンドからなる群から選択された少なくとも1種を含む、請求の範囲第1項に記載された基板。 The said board | substrate (1, 3, 5, 8, 11, 12, 15, 20) contains at least 1 sort (s) selected from the group which consists of SiC, GaN, a sapphire, AlN, a diamond, The Claim 1st Claim Substrate.
  5.  透明な基板(1、3、5、8、11、12、15、20)を準備する工程(S10)と、
     前記基板(1、3、5、8、11、12、15、20)の端部の少なくとも一部における光の透過率を、前記基板の中央部における前記光の透過率よりも小さくする加工を行なう工程(S20)とを備える、基板の製造方法。
    A step (S10) of preparing a transparent substrate (1, 3, 5, 8, 11, 12, 15, 20);
    Processing to make the light transmittance in at least a part of the end portion of the substrate (1, 3, 5, 8, 11, 12, 15, 20) smaller than the light transmittance in the central portion of the substrate. A step of performing (S20).
  6.  前記加工を行なう工程(S20)には、前記端部の少なくとも一部に入射する前記光を全反射する全反射面(2)を形成する工程を含む、請求の範囲第5項に記載の基板の製造方法。 6. The substrate according to claim 5, wherein the processing (S20) includes a step of forming a total reflection surface (2) that totally reflects the light incident on at least a part of the end portion. Manufacturing method.
  7.  前記全反射面(2)を形成する工程には、前記端部の少なくとも一部を機械加工する工程を含む、請求の範囲第6項に記載の基板の製造方法。 The method for manufacturing a substrate according to claim 6, wherein the step of forming the total reflection surface (2) includes a step of machining at least a part of the end portion.
  8.  前記全反射面(2)を形成する工程には、前記端部の少なくとも一部をレーザ加工する工程を含む、請求の範囲第6項に記載の基板の製造方法。 The method for manufacturing a substrate according to claim 6, wherein the step of forming the total reflection surface (2) includes a step of laser processing at least a part of the end portion.
  9.  前記加工を行なう工程(S20)には、前記端部の少なくとも一部に入射する光を乱反射する乱反射面(9)を形成する工程を含む、請求の範囲第5項に記載の基板の製造方法。 The method for manufacturing a substrate according to claim 5, wherein the step (S20) of performing the processing includes a step of forming an irregular reflection surface (9) for irregularly reflecting light incident on at least a part of the end portion. .
  10.  前記乱反射面(9)を形成する工程には、前記端部の少なくとも一部を機械加工する工程を含む、請求の範囲第9項に記載の基板の製造方法。 The method for manufacturing a substrate according to claim 9, wherein the step of forming the irregular reflection surface (9) includes a step of machining at least a part of the end portion.
  11.  前記乱反射面(9)を形成する工程には、前記端部の少なくとも一部をレーザ加工する工程を含む、請求の範囲第9項に記載の基板の製造方法。 The method for manufacturing a substrate according to claim 9, wherein the step of forming the irregular reflection surface (9) includes a step of laser processing at least a part of the end portion.
  12.  前記乱反射面(9)を形成する工程には、前記端部の少なくとも一部に不純物の導入を行なう工程(S21)と、前記不純物を導入した領域の表面の面粗度を上げる工程(S22、S23)とを含む、請求の範囲第9項に記載の基板の製造方法。 In the step of forming the irregular reflection surface (9), a step of introducing impurities into at least a part of the end portion (S21), and a step of increasing the surface roughness of the surface into which the impurities are introduced (S22, A method for manufacturing a substrate according to claim 9, comprising S23).
  13.  前記面粗度を上げる工程(S22、S23)には、前記領域の表面層をエッチングする工程(S22)または前記領域の表面層を熱処理する工程(S23)を含む、請求の範囲第12項に記載の基板の製造方法。 The step (S22, S23) of increasing the surface roughness includes a step (S22) of etching a surface layer of the region or a step of heat treating the surface layer of the region (S23). The manufacturing method of the board | substrate of description.
  14.  前記乱反射面(9)を形成する工程には、前記端部の少なくとも一部に薄膜(16)を成膜する工程を含む、請求の範囲第9項に記載の基板の製造方法。 The method of manufacturing a substrate according to claim 9, wherein the step of forming the irregular reflection surface (9) includes a step of forming a thin film (16) on at least a part of the end portion.
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